Minimum Spanning Trees


 Phebe Gregory
 1 years ago
 Views:
Transcription
1 Minimum Spanning Trees Algorithms and Presentation
2 Outline 1 Graph Terminology Minimum Spanning Trees 2 3
3 Outline Graph Terminology Minimum Spanning Trees 1 Graph Terminology Minimum Spanning Trees 2 3
4 Graphs Graph Terminology Minimum Spanning Trees In graph theory, a graph is an ordered pair G = (V, E) comprising a set of vertices or nodes together with a set of edges. Edges are 2element subsets of V which represent a connection between two vertices. Edges can either be directed or undirected. Edges can also have a weight attribute.
5 Graphs Graph Terminology Minimum Spanning Trees In graph theory, a graph is an ordered pair G = (V, E) comprising a set of vertices or nodes together with a set of edges. Edges are 2element subsets of V which represent a connection between two vertices. Edges can either be directed or undirected. Edges can also have a weight attribute.
6 Graphs Graph Terminology Minimum Spanning Trees In graph theory, a graph is an ordered pair G = (V, E) comprising a set of vertices or nodes together with a set of edges. Edges are 2element subsets of V which represent a connection between two vertices. Edges can either be directed or undirected. Edges can also have a weight attribute.
7 Graphs Graph Terminology Minimum Spanning Trees In graph theory, a graph is an ordered pair G = (V, E) comprising a set of vertices or nodes together with a set of edges. Edges are 2element subsets of V which represent a connection between two vertices. Edges can either be directed or undirected. Edges can also have a weight attribute.
8 Connectivity Graph Terminology Minimum Spanning Trees A graph is connected when there is a path between every pair of vertices. A cycle is a path that starts and ends with the same vertex. A tree is a connected, acyclic graph.
9 Connectivity Graph Terminology Minimum Spanning Trees A graph is connected when there is a path between every pair of vertices. A cycle is a path that starts and ends with the same vertex. A tree is a connected, acyclic graph.
10 Connectivity Graph Terminology Minimum Spanning Trees A graph is connected when there is a path between every pair of vertices. A cycle is a path that starts and ends with the same vertex. A tree is a connected, acyclic graph.
11 Outline Graph Terminology Minimum Spanning Trees 1 Graph Terminology Minimum Spanning Trees 2 3
12 Spanning Trees Graph Terminology Minimum Spanning Trees Formally, for a graph G = (V, E), the spanning tree is E E such that: u V : (u, v) E (v, u) E v V In other words: the subset of edges spans all vertices. E = V 1 In other words: the number of edges is one less than the number of vertices, so that there are no cycles.
13 Spanning Trees Graph Terminology Minimum Spanning Trees Formally, for a graph G = (V, E), the spanning tree is E E such that: u V : (u, v) E (v, u) E v V In other words: the subset of edges spans all vertices. E = V 1 In other words: the number of edges is one less than the number of vertices, so that there are no cycles.
14 Spanning Trees Graph Terminology Minimum Spanning Trees Formally, for a graph G = (V, E), the spanning tree is E E such that: u V : (u, v) E (v, u) E v V In other words: the subset of edges spans all vertices. Linear Graph E = V 1 In other words: the number of edges is one less than the number of vertices, so that there are no cycles.
15 Graph Terminology Minimum Spanning Trees What Makes A Spanning Tree The Minimum? MST Criterion: When the sum of the edge weights in a spanning tree is the minimum over all spanning trees of a graph Figure: Suppose (b, f ) is removed and (c, f ) is added...
16 Outline 1 Graph Terminology Minimum Spanning Trees 2 3
17 Main Idea Start with V disjoint components. Consider lesser weight edges first to incrementally connect components. Make certain to avoid cycles. Continue until spanning tree is created.
18 Main Idea Start with V disjoint components. Consider lesser weight edges first to incrementally connect components. Make certain to avoid cycles. Continue until spanning tree is created.
19 Main Idea Start with V disjoint components. Consider lesser weight edges first to incrementally connect components. Make certain to avoid cycles. Continue until spanning tree is created.
20 Main Idea Start with V disjoint components. Consider lesser weight edges first to incrementally connect components. Make certain to avoid cycles. Continue until spanning tree is created.
21 Pseudocode 1 A = 0 2 foreach v G.V : 3 MAKESET(v) 4 foreach (u, v) ordered by weight(u, v), increasing: 5 if FINDSET (u) FINDSET (v): 6 A = A (u, v) 7 UNION(u, v) 8 return A
22 Example
23 Example
24 Example
25 Example
26 Example
27 Example
28 Proof Of Correctness Spanning Tree Validity By avoiding connecting two already connected vertices, output has no cycles. If G is connected, output must be connected. Minimality Consider a lesser total weight spanning tree with at least one different edge e = (u, v). If e leads to less weight, then e would have been considered before some edge that connects u and v in our output.
29 Proof Of Correctness Spanning Tree Validity By avoiding connecting two already connected vertices, output has no cycles. If G is connected, output must be connected. Minimality Consider a lesser total weight spanning tree with at least one different edge e = (u, v). If e leads to less weight, then e would have been considered before some edge that connects u and v in our output.
30 Proof Of Correctness Spanning Tree Validity By avoiding connecting two already connected vertices, output has no cycles. If G is connected, output must be connected. Minimality Consider a lesser total weight spanning tree with at least one different edge e = (u, v). If e leads to less weight, then e would have been considered before some edge that connects u and v in our output.
31 Proof Of Correctness Spanning Tree Validity By avoiding connecting two already connected vertices, output has no cycles. If G is connected, output must be connected. Minimality Consider a lesser total weight spanning tree with at least one different edge e = (u, v). If e leads to less weight, then e would have been considered before some edge that connects u and v in our output.
32 Proof Of Correctness Spanning Tree Validity By avoiding connecting two already connected vertices, output has no cycles. If G is connected, output must be connected. Minimality Consider a lesser total weight spanning tree with at least one different edge e = (u, v). If e leads to less weight, then e would have been considered before some edge that connects u and v in our output.
33 Proof Of Correctness Spanning Tree Validity By avoiding connecting two already connected vertices, output has no cycles. If G is connected, output must be connected. Minimality Consider a lesser total weight spanning tree with at least one different edge e = (u, v). If e leads to less weight, then e would have been considered before some edge that connects u and v in our output.
34 Outline 1 Graph Terminology Minimum Spanning Trees 2 3
35 Main Idea Start with one (any) vertex. Branch outwards to grow your connected component. Consider only edges that leave the connected component. Add smallest considered edge to your connected component. Continue until a spanning tree is created.
36 Main Idea Start with one (any) vertex. Branch outwards to grow your connected component. Consider only edges that leave the connected component. Add smallest considered edge to your connected component. Continue until a spanning tree is created.
37 Main Idea Start with one (any) vertex. Branch outwards to grow your connected component. Consider only edges that leave the connected component. Add smallest considered edge to your connected component. Continue until a spanning tree is created.
38 Main Idea Start with one (any) vertex. Branch outwards to grow your connected component. Consider only edges that leave the connected component. Add smallest considered edge to your connected component. Continue until a spanning tree is created.
39 Main Idea Start with one (any) vertex. Branch outwards to grow your connected component. Consider only edges that leave the connected component. Add smallest considered edge to your connected component. Continue until a spanning tree is created.
40 Example
41 Proof of Correctness Both the spanning tree and minimality argument are nearly identical for Prim s as they are for Kruskal s.
42 Some Taxonomy Clustering Analysis Traveling Salesman Problem Approximation
Outline. NPcompleteness. When is a problem easy? When is a problem hard? Today. Euler Circuits
Outline NPcompleteness Examples of Easy vs. Hard problems Euler circuit vs. Hamiltonian circuit Shortest Path vs. Longest Path 2pairs sum vs. general Subset Sum Reducing one problem to another Clique
More informationGRAPH THEORY and APPLICATIONS. Trees
GRAPH THEORY and APPLICATIONS Trees Properties Tree: a connected graph with no cycle (acyclic) Forest: a graph with no cycle Paths are trees. Star: A tree consisting of one vertex adjacent to all the others.
More information2.3 Scheduling jobs on identical parallel machines
2.3 Scheduling jobs on identical parallel machines There are jobs to be processed, and there are identical machines (running in parallel) to which each job may be assigned Each job = 1,,, must be processed
More informationMath 443/543 Graph Theory Notes 4: Connector Problems
Math 443/543 Graph Theory Notes 4: Connector Problems David Glickenstein September 19, 2012 1 Trees and the Minimal Connector Problem Here is the problem: Suppose we have a collection of cities which we
More informationGraph. Consider a graph, G in Fig Then the vertex V and edge E can be represented as:
Graph A graph G consist of 1. Set of vertices V (called nodes), (V = {v1, v2, v3, v4...}) and 2. Set of edges E (i.e., E {e1, e2, e3...cm} A graph can be represents as G = (V, E), where V is a finite and
More informationChapter 4. Trees. 4.1 Basics
Chapter 4 Trees 4.1 Basics A tree is a connected graph with no cycles. A forest is a collection of trees. A vertex of degree one, particularly in a tree, is called a leaf. Trees arise in a variety of applications.
More information2. (a) Explain the strassen s matrix multiplication. (b) Write deletion algorithm, of Binary search tree. [8+8]
Code No: R05220502 Set No. 1 1. (a) Describe the performance analysis in detail. (b) Show that f 1 (n)+f 2 (n) = 0(max(g 1 (n), g 2 (n)) where f 1 (n) = 0(g 1 (n)) and f 2 (n) = 0(g 2 (n)). [8+8] 2. (a)
More informationPlanar Graph and Trees
Dr. Nahid Sultana December 16, 2012 Tree Spanning Trees Minimum Spanning Trees Maps and Regions Eulers Formula Nonplanar graph Dual Maps and the Four Color Theorem Tree Spanning Trees Minimum Spanning
More informationSolutions to Exercises 8
Discrete Mathematics Lent 2009 MA210 Solutions to Exercises 8 (1) Suppose that G is a graph in which every vertex has degree at least k, where k 1, and in which every cycle contains at least 4 vertices.
More informationCSE 326, Data Structures. Sample Final Exam. Problem Max Points Score 1 14 (2x7) 2 18 (3x6) 3 4 4 7 5 9 6 16 7 8 8 4 9 8 10 4 Total 92.
Name: Email ID: CSE 326, Data Structures Section: Sample Final Exam Instructions: The exam is closed book, closed notes. Unless otherwise stated, N denotes the number of elements in the data structure
More informationLecture Notes on Spanning Trees
Lecture Notes on Spanning Trees 15122: Principles of Imperative Computation Frank Pfenning Lecture 26 April 26, 2011 1 Introduction In this lecture we introduce graphs. Graphs provide a uniform model
More informationA tree can be defined in a variety of ways as is shown in the following theorem: 2. There exists a unique path between every two vertices of G.
7 Basic Properties 24 TREES 7 Basic Properties Definition 7.1: A connected graph G is called a tree if the removal of any of its edges makes G disconnected. A tree can be defined in a variety of ways as
More informationJade Yu Cheng ICS 311 Homework 10 Oct 7, 2008
Jade Yu Cheng ICS 311 Homework 10 Oct 7, 2008 Question for lecture 13 Problem 233 on p. 577 Bottleneck spanning tree A bottleneck spanning tree of an undirected graph is a spanning tree of whose largest
More informationGraphs and Network Flows IE411 Lecture 1
Graphs and Network Flows IE411 Lecture 1 Dr. Ted Ralphs IE411 Lecture 1 1 References for Today s Lecture Required reading Sections 17.1, 19.1 References AMO Chapter 1 and Section 2.1 and 2.2 IE411 Lecture
More informationAnalysis of Algorithms, I
Analysis of Algorithms, I CSOR W4231.002 Eleni Drinea Computer Science Department Columbia University Thursday, February 26, 2015 Outline 1 Recap 2 Representing graphs 3 Breadthfirst search (BFS) 4 Applications
More informationCMSC 451: Graph Properties, DFS, BFS, etc.
CMSC 451: Graph Properties, DFS, BFS, etc. Slides By: Carl Kingsford Department of Computer Science University of Maryland, College Park Based on Chapter 3 of Algorithm Design by Kleinberg & Tardos. Graphs
More informationCSE 373 Analysis of Algorithms Date: Nov. 1, Solution to HW3. Total Points: 100
CSE 373 Analysis of Algorithms Date: Nov. 1, 2016 Steven Skiena Problem 1 54 [5] Solution to HW3 Total Points: 100 Let T be the BFStree of the graph G. For any e in G and e T, we have to show that e
More informationThe UnionFind Problem Kruskal s algorithm for finding an MST presented us with a problem in datastructure design. As we looked at each edge,
The UnionFind Problem Kruskal s algorithm for finding an MST presented us with a problem in datastructure design. As we looked at each edge, cheapest first, we had to determine whether its two endpoints
More informationData Structures and Algorithms Written Examination
Data Structures and Algorithms Written Examination 22 February 2013 FIRST NAME STUDENT NUMBER LAST NAME SIGNATURE Instructions for students: Write First Name, Last Name, Student Number and Signature where
More informationOPTIMAL DESIGN OF DISTRIBUTED SENSOR NETWORKS FOR FIELD RECONSTRUCTION
OPTIMAL DESIGN OF DISTRIBUTED SENSOR NETWORKS FOR FIELD RECONSTRUCTION Sérgio Pequito, Stephen Kruzick, Soummya Kar, José M. F. Moura, A. Pedro Aguiar Department of Electrical and Computer Engineering
More information1 Digraphs. Definition 1
1 Digraphs Definition 1 Adigraphordirected graphgisatriplecomprisedofavertex set V(G), edge set E(G), and a function assigning each edge an ordered pair of vertices (tail, head); these vertices together
More informationWhy? A central concept in Computer Science. Algorithms are ubiquitous.
Analysis of Algorithms: A Brief Introduction Why? A central concept in Computer Science. Algorithms are ubiquitous. Using the Internet (sending email, transferring files, use of search engines, online
More informationSocial Media Mining. Graph Essentials
Graph Essentials Graph Basics Measures Graph and Essentials Metrics 2 2 Nodes and Edges A network is a graph nodes, actors, or vertices (plural of vertex) Connections, edges or ties Edge Node Measures
More informationCOT5405 Analysis of Algorithms Homework 3 Solutions
COT0 Analysis of Algorithms Homework 3 Solutions. Prove or give a counter example: (a) In the textbook, we have two routines for graph traversal  DFS(G) and BFS(G,s)  where G is a graph and s is any
More informationTheorem A graph T is a tree if, and only if, every two distinct vertices of T are joined by a unique path.
Chapter 3 Trees Section 3. Fundamental Properties of Trees Suppose your city is planning to construct a rapid rail system. They want to construct the most economical system possible that will meet the
More informationComputer Algorithms. NPComplete Problems. CISC 4080 Yanjun Li
Computer Algorithms NPComplete Problems NPcompleteness The quest for efficient algorithms is about finding clever ways to bypass the process of exhaustive search, using clues from the input in order
More informationHandout #Ch7 San Skulrattanakulchai Gustavus Adolphus College Dec 6, 2010. Chapter 7: Digraphs
MCS236: Graph Theory Handout #Ch7 San Skulrattanakulchai Gustavus Adolphus College Dec 6, 2010 Chapter 7: Digraphs Strong Digraphs Definitions. A digraph is an ordered pair (V, E), where V is the set
More information/ Approximation Algorithms Lecturer: Michael Dinitz Topic: Steiner Tree and TSP Date: 01/29/15 Scribe: Katie Henry
600.469 / 600.669 Approximation Algorithms Lecturer: Michael Dinitz Topic: Steiner Tree and TSP Date: 01/29/15 Scribe: Katie Henry 2.1 Steiner Tree Definition 2.1.1 In the Steiner Tree problem the input
More informationHomework 15 Solutions
PROBLEM ONE (Trees) Homework 15 Solutions 1. Recall the definition of a tree: a tree is a connected, undirected graph which has no cycles. Which of the following definitions are equivalent to this definition
More informationChapter 4: Trees. 2. Theorem: Let T be a graph with n vertices. Then the following statements are equivalent:
9 Properties of Trees. Definitions: Chapter 4: Trees forest  a graph that contains no cycles tree  a connected forest. Theorem: Let T be a graph with n vertices. Then the following statements are equivalent:
More informationIE 680 Special Topics in Production Systems: Networks, Routing and Logistics*
IE 680 Special Topics in Production Systems: Networks, Routing and Logistics* Rakesh Nagi Department of Industrial Engineering University at Buffalo (SUNY) *Lecture notes from Network Flows by Ahuja, Magnanti
More information1 Representing Graphs With Arrays
Lecture 0 Shortest Weighted Paths I Parallel and Sequential Data Structures and Algorithms, 520 (Spring 202) Lectured by Margaret ReidMiller 6 February 202 Today:  Representing Graphs with Arrays 
More informationData Structures in Java. Session 16 Instructor: Bert Huang
Data Structures in Java Session 16 Instructor: Bert Huang http://www.cs.columbia.edu/~bert/courses/3134 Announcements Homework 4 due next class Remaining grades: hw4, hw5, hw6 25% Final exam 30% Midterm
More informationPolygon Triangulation. O Rourke, Chapter 1
Polygon Triangulation O Rourke, Chapter 1 Outline Triangulation Duals Three Coloring Art Gallery Problem Definition A (simple) polygon is a region of the plane bounded by a finite collection of line segments
More informationA. V. Gerbessiotis CS Spring 2014 PS 3 Mar 24, 2014 No points
A. V. Gerbessiotis CS 610102 Spring 2014 PS 3 Mar 24, 2014 No points Problem 1. Suppose that we insert n keys into a hash table of size m using open addressing and uniform hashing. Let p(n, m) be the
More informationCSE 20: Discrete Mathematics for Computer Science. Prof. Miles Jones. Today s Topics: Graphs. The Internet graph
Today s Topics: CSE 0: Discrete Mathematics for Computer Science Prof. Miles Jones. Graphs. Some theorems on graphs. Eulerian graphs Graphs! Model relations between pairs of objects The Internet graph!
More informationPart 2: Community Detection
Chapter 8: Graph Data Part 2: Community Detection Based on Leskovec, Rajaraman, Ullman 2014: Mining of Massive Datasets Big Data Management and Analytics Outline Community Detection  Social networks 
More information3. Markov property. Markov property for MRFs. HammersleyClifford theorem. Markov property for Bayesian networks. Imap, Pmap, and chordal graphs
Markov property 33. Markov property Markov property for MRFs HammersleyClifford theorem Markov property for ayesian networks Imap, Pmap, and chordal graphs Markov Chain X Y Z X = Z Y µ(x, Y, Z) = f(x,
More informationSolutions to Homework 6
Solutions to Homework 6 Debasish Das EECS Department, Northwestern University ddas@northwestern.edu 1 Problem 5.24 We want to find light spanning trees with certain special properties. Given is one example
More informationV. Adamchik 1. Graph Theory. Victor Adamchik. Fall of 2005
V. Adamchik 1 Graph Theory Victor Adamchik Fall of 2005 Plan 1. Basic Vocabulary 2. Regular graph 3. Connectivity 4. Representing Graphs Introduction A.Aho and J.Ulman acknowledge that Fundamentally, computer
More informationSample Problems in Discrete Mathematics
Sample Problems in Discrete Mathematics This handout lists some sample problems that you should be able to solve as a prerequisite to Computer Algorithms Try to solve all of them You should also read
More informationGraph Algorithms using MapReduce
Graph Algorithms using MapReduce Graphs are ubiquitous in modern society. Some examples: The hyperlink structure of the web 1/7 Graph Algorithms using MapReduce Graphs are ubiquitous in modern society.
More informationMGF 1107 CH 15 LECTURE NOTES Denson. Section 15.1
1 Section 15.1 Consider the house plan below. This graph represents the house. Consider the mail route below. This graph represents the mail route. 2 Definitions 1. Graph a structure that describes relationships.
More information1 Basic Definitions and Concepts in Graph Theory
CME 305: Discrete Mathematics and Algorithms 1 Basic Definitions and Concepts in Graph Theory A graph G(V, E) is a set V of vertices and a set E of edges. In an undirected graph, an edge is an unordered
More informationCMPSCI611: Approximating MAXCUT Lecture 20
CMPSCI611: Approximating MAXCUT Lecture 20 For the next two lectures we ll be seeing examples of approximation algorithms for interesting NPhard problems. Today we consider MAXCUT, which we proved to
More informationLesson 3. Algebraic graph theory. Sergio Barbarossa. Rome  February 2010
Lesson 3 Algebraic graph theory Sergio Barbarossa Basic notions Definition: A directed graph (or digraph) composed by a set of vertices and a set of edges We adopt the convention that the information flows
More informationCMPS 102 Solutions to Homework 1
CMPS 0 Solutions to Homework Lindsay Brown, lbrown@soe.ucsc.edu September 9, 005 Problem.. p. 3 For inputs of size n insertion sort runs in 8n steps, while merge sort runs in 64n lg n steps. For which
More informationSEMITOTAL AND TOTAL BLOCKCUTVERTEX GRAPH
CHAPTER 3 SEMITOTAL AND TOTAL BLOCKCUTVERTEX GRAPH ABSTRACT This chapter begins with the notion of block distances in graphs. Using block distance we defined the central tendencies of a block, like Bradius
More informationChapter 6: Graph Theory
Chapter 6: Graph Theory Graph theory deals with routing and network problems and if it is possible to find a best route, whether that means the least expensive, least amount of time or the least distance.
More information3. The Junction Tree Algorithms
A Short Course on Graphical Models 3. The Junction Tree Algorithms Mark Paskin mark@paskin.org 1 Review: conditional independence Two random variables X and Y are independent (written X Y ) iff p X ( )
More informationHeuristics and Local Search. Version 2 c 2009, 2001 José Fernando Oliveira, Maria Antónia Carravilla FEUP
Heuristics and Local Search Version c 009, 001 José Fernando Oliveira, Maria Antónia Carravilla FEUP Approximate methods to solve combinatorial optimization problems Heuristics Aim to efficiently generate
More informationDATA ANALYSIS II. Matrix Algorithms
DATA ANALYSIS II Matrix Algorithms Similarity Matrix Given a dataset D = {x i }, i=1,..,n consisting of n points in R d, let A denote the n n symmetric similarity matrix between the points, given as where
More informationLecture 15 An Arithmetic Circuit Lowerbound and Flows in Graphs
CSE599s: Extremal Combinatorics November 21, 2011 Lecture 15 An Arithmetic Circuit Lowerbound and Flows in Graphs Lecturer: Anup Rao 1 An Arithmetic Circuit Lower Bound An arithmetic circuit is just like
More informationGraph Algorithms. Ananth Grama, Anshul Gupta, George Karypis, and Vipin Kumar
Graph Algorithms Ananth Grama, Anshul Gupta, George Karypis, and Vipin Kumar To accompany the text Introduction to Parallel Computing, Addison Wesley, 3. Topic Overview Definitions and Representation Minimum
More informationCMPT 280 Intermediate Data Structures and Algorithms
The University of Saskatchewan Saskatoon, Canada Department of Computer Science CMPT 280 Intermediate Data Structures and Algorithms 1 Purpose Assignment 5 Date Due: February 23, 2010, 10:00pm The purpose
More informationScheduling. Open shop, job shop, flow shop scheduling. Related problems. Open shop, job shop, flow shop scheduling
Scheduling Basic scheduling problems: open shop, job shop, flow job The disjunctive graph representation Algorithms for solving the job shop problem Computational complexity of the job shop problem Open
More informationBasic Notions on Graphs. Planar Graphs and Vertex Colourings. Joe Ryan. Presented by
Basic Notions on Graphs Planar Graphs and Vertex Colourings Presented by Joe Ryan School of Electrical Engineering and Computer Science University of Newcastle, Australia Planar graphs Graphs may be drawn
More informationFast Algorithms for Connectivity Problems in Networks
Fast Algorithms for Connectivity Problems in Networks Steiner Cuts, GomoryHu Trees, and Edge Splitting Strand Life Sciences 29 May 2008/ MCDES The Setting A network G of n nodes and m edges. Many nodes,
More information1. Sorting (assuming sorting into ascending order) a) BUBBLE SORT
DECISION 1 Revision Notes 1. Sorting (assuming sorting into ascending order) a) BUBBLE SORT Make sure you show comparisons clearly and label each pass First Pass 8 4 3 6 1 4 8 3 6 1 4 3 8 6 1 4 3 6 8 1
More informationEuler Paths and Euler Circuits
Euler Paths and Euler Circuits An Euler path is a path that uses every edge of a graph exactly once. An Euler circuit is a circuit that uses every edge of a graph exactly once. An Euler path starts and
More informationClipping polygons the SutherlandHodgman algorithm
Clipping polygons would seem to be quite complex. Clipping polygons would seem to be quite complex. single Clipping polygons would seem to be quite complex. single Clipping polygons would seem to be quite
More informationLecture 7: Approximation via Randomized Rounding
Lecture 7: Approximation via Randomized Rounding Often LPs return a fractional solution where the solution x, which is supposed to be in {0, } n, is in [0, ] n instead. There is a generic way of obtaining
More informationData Structures in Java. Session 15 Instructor: Bert Huang http://www1.cs.columbia.edu/~bert/courses/3134
Data Structures in Java Session 15 Instructor: Bert Huang http://www1.cs.columbia.edu/~bert/courses/3134 Announcements Homework 4 on website No class on Tuesday Midterm grades almost done Review Indexing
More informationCSPs: Arc Consistency
CSPs: Arc Consistency CPSC 322 CSPs 3 Textbook 4.5 CSPs: Arc Consistency CPSC 322 CSPs 3, Slide 1 Lecture Overview 1 Recap 2 Consistency 3 Arc Consistency CSPs: Arc Consistency CPSC 322 CSPs 3, Slide 2
More informationAlgorithm Design and Analysis
Algorithm Design and Analysis LECTURE 27 Approximation Algorithms Load Balancing Weighted Vertex Cover Reminder: Fill out SRTEs online Don t forget to click submit Sofya Raskhodnikova 12/6/2011 S. Raskhodnikova;
More informationCIS 700: algorithms for Big Data
CIS 700: algorithms for Big Data Lecture 6: Graph Sketching Slides at http://grigory.us/bigdataclass.html Grigory Yaroslavtsev http://grigory.us Sketching Graphs? We know how to sketch vectors: v Mv
More informationLecture 7: NPComplete Problems
IAS/PCMI Summer Session 2000 Clay Mathematics Undergraduate Program Basic Course on Computational Complexity Lecture 7: NPComplete Problems David Mix Barrington and Alexis Maciel July 25, 2000 1. Circuit
More informationThe Classes P and NP. mohamed@elwakil.net
Intractable Problems The Classes P and NP Mohamed M. El Wakil mohamed@elwakil.net 1 Agenda 1. What is a problem? 2. Decidable or not? 3. The P class 4. The NP Class 5. TheNP Complete class 2 What is a
More informationUSE OF EIGENVALUES AND EIGENVECTORS TO ANALYZE BIPARTIVITY OF NETWORK GRAPHS
USE OF EIGENVALUES AND EIGENVECTORS TO ANALYZE BIPARTIVITY OF NETWORK GRAPHS Natarajan Meghanathan Jackson State University, 1400 Lynch St, Jackson, MS, USA natarajan.meghanathan@jsums.edu ABSTRACT This
More informationAbout the Tutorial. Audience. Prerequisites. Disclaimer & Copyright
About the Tutorial This tutorial offers a brief introduction to the fundamentals of graph theory. Written in a readerfriendly style, it covers the types of graphs, their properties, trees, graph traversability,
More informationTrees and Fundamental Circuits
Trees and Fundamental Circuits Tree A connected graph without any circuits. o must have at least one vertex. o definition implies that it must be a simple graph. o only finite trees are being considered
More informationPartitioning Constraint
Treebased Graph Partitioning Constraint Xavier Lorca Series Editor Narendra Jussien WILEY Table of Contents Part 1. Constraint Programming and Foundations of Graph Theory 1 Introduction to Part 1 3 Chapter
More informationGraph Theory and Complex Networks: An Introduction. Chapter 06: Network analysis
Graph Theory and Complex Networks: An Introduction Maarten van Steen VU Amsterdam, Dept. Computer Science Room R4.0, steen@cs.vu.nl Chapter 06: Network analysis Version: April 8, 04 / 3 Contents Chapter
More informationThe edge slide graph of the ndimensional cube
The edge slide graph of the ndimensional cube Howida AL Fran Institute of Fundamental Sciences Massey University, Manawatu 8th Australia New Zealand Mathematics Convention December 2014 Howida AL Fran
More informationForests and Trees: A forest is a graph with no cycles, a tree is a connected forest.
2 Trees What is a tree? Forests and Trees: A forest is a graph with no cycles, a tree is a connected forest. Theorem 2.1 If G is a forest, then comp(g) = V (G) E(G). Proof: We proceed by induction on E(G).
More informationIntroduction to Algorithms Review information for Prelim 1 CS 4820, Spring 2010 Distributed Wednesday, February 24
Introduction to Algorithms Review information for Prelim 1 CS 4820, Spring 2010 Distributed Wednesday, February 24 The final exam will cover seven topics. 1. greedy algorithms 2. divideandconquer algorithms
More informationSCAN: A Structural Clustering Algorithm for Networks
SCAN: A Structural Clustering Algorithm for Networks Xiaowei Xu, Nurcan Yuruk, Zhidan Feng (University of Arkansas at Little Rock) Thomas A. J. Schweiger (Acxiom Corporation) Networks scaling: #edges connected
More informationOn the kpath cover problem for cacti
On the kpath cover problem for cacti Zemin Jin and Xueliang Li Center for Combinatorics and LPMC Nankai University Tianjin 300071, P.R. China zeminjin@eyou.com, x.li@eyou.com Abstract In this paper we
More informationThe origins of graph theory are humble, even frivolous. Biggs, E. K. Lloyd, and R. J. Wilson)
Chapter 11 Graph Theory The origins of graph theory are humble, even frivolous. Biggs, E. K. Lloyd, and R. J. Wilson) (N. Let us start with a formal definition of what is a graph. Definition 72. A graph
More informationCSL851: Algorithmic Graph Theory Semester I Lecture 1: July 24
CSL851: Algorithmic Graph Theory Semester I 20132014 Lecture 1: July 24 Lecturer: Naveen Garg Scribes: Suyash Roongta Note: LaTeX template courtesy of UC Berkeley EECS dept. Disclaimer: These notes have
More informationSimple Graphs Degrees, Isomorphism, Paths
Mathematics for Computer Science MIT 6.042J/18.062J Simple Graphs Degrees, Isomorphism, Types of Graphs Simple Graph this week MultiGraph Directed Graph next week Albert R Meyer, March 10, 2010 lec 6W.1
More informationExamples and Proofs of Inference in Junction Trees
Examples and Proofs of Inference in Junction Trees Peter Lucas LIAC, Leiden University February 4, 2016 1 Representation and notation Let P(V) be a joint probability distribution, where V stands for a
More informationCombinatorics: The Fine Art of Counting
Combinatorics: The Fine Art of Counting Week 9 Lecture Notes Graph Theory For completeness I have included the definitions from last week s lecture which we will be using in today s lecture along with
More informationApproximation Algorithms
Approximation Algorithms or: How I Learned to Stop Worrying and Deal with NPCompleteness Ong Jit Sheng, Jonathan (A0073924B) March, 2012 Overview Key Results (I) General techniques: Greedy algorithms
More information1. Nondeterministically guess a solution (called a certificate) 2. Check whether the solution solves the problem (called verification)
Some N P problems Computer scientists have studied many N P problems, that is, problems that can be solved nondeterministically in polynomial time. Traditionally complexity question are studied as languages:
More information6.042/18.062J Mathematics for Computer Science October 3, 2006 Tom Leighton and Ronitt Rubinfeld. Graph Theory III
6.04/8.06J Mathematics for Computer Science October 3, 006 Tom Leighton and Ronitt Rubinfeld Lecture Notes Graph Theory III Draft: please check back in a couple of days for a modified version of these
More information8.1 Min Degree Spanning Tree
CS880: Approximations Algorithms Scribe: Siddharth Barman Lecturer: Shuchi Chawla Topic: Min Degree Spanning Tree Date: 02/15/07 In this lecture we give a local search based algorithm for the Min Degree
More information(a) (b) (c) Figure 1 : Graphs, multigraphs and digraphs. If the vertices of the leftmost figure are labelled {1, 2, 3, 4} in clockwise order from
4 Graph Theory Throughout these notes, a graph G is a pair (V, E) where V is a set and E is a set of unordered pairs of elements of V. The elements of V are called vertices and the elements of E are called
More informationGraph definition Degree, in, out degree, oriented graph. Complete, regular, bipartite graph. Graph representation, connectivity, adjacency.
Mária Markošová Graph definition Degree, in, out degree, oriented graph. Complete, regular, bipartite graph. Graph representation, connectivity, adjacency. Isomorphism of graphs. Paths, cycles, trials.
More informationGraph Theory. Introduction. Distance in Graphs. Trees. Isabela Drămnesc UVT. Computer Science Department, West University of Timişoara, Romania
Graph Theory Introduction. Distance in Graphs. Trees Isabela Drămnesc UVT Computer Science Department, West University of Timişoara, Romania November 2016 Isabela Drămnesc UVT Graph Theory and Combinatorics
More informationMean RamseyTurán numbers
Mean RamseyTurán numbers Raphael Yuster Department of Mathematics University of Haifa at Oranim Tivon 36006, Israel Abstract A ρmean coloring of a graph is a coloring of the edges such that the average
More informationB AB 5 C AC 3 D ABGED 9 E ABGE 7 F ABGEF 8 G ABG 6 A BEDA 3 C BC 1 D BCD 2 E BE 1 F BEF 2 G BG 1
p.9 9.5 a. Find the shortest path from A to all other vertices for the graph in Figure 9.8. b. Find the shortest unweighted path from B to all other vertices for the graph in Figure 9.8. A 5 B C 7 7 6
More informationGraphs. Graph G=(V,E): representation
Graphs G = (V,E) V the vertices of the graph {v 1, v 2,..., v n } E the edges; E a subset of V x V A cost function cij is the cost/ weight of the edge (v i, v j ) Graph G=(V,E): representation 1. Adjacency
More informationLecture 10 UnionFind The unionnd data structure is motivated by Kruskal's minimum spanning tree algorithm (Algorithm 2.6), in which we needed two operations on disjoint sets of vertices: determine whether
More informationComputational Approach for Assessment of Critical Infrastructure in Network Systems
Computational Approach for Assessment of Critical Infrastructure in Network Systems EMIL KELEVEDJIEV 1 Institute of Mathematics and Informatics Bulgarian Academy of Sciences ABSTRACT. Methods of computational
More informationDiscrete Mathematics & Mathematical Reasoning Chapter 10: Graphs
Discrete Mathematics & Mathematical Reasoning Chapter 10: Graphs Kousha Etessami U. of Edinburgh, UK Kousha Etessami (U. of Edinburgh, UK) Discrete Mathematics (Chapter 6) 1 / 13 Overview Graphs and Graph
More informationComputational Geometry. Lecture 1: Introduction and Convex Hulls
Lecture 1: Introduction and convex hulls 1 Geometry: points, lines,... Plane (twodimensional), R 2 Space (threedimensional), R 3 Space (higherdimensional), R d A point in the plane, 3dimensional space,
More informationFinding and counting given length cycles
Finding and counting given length cycles Noga Alon Raphael Yuster Uri Zwick Abstract We present an assortment of methods for finding and counting simple cycles of a given length in directed and undirected
More informationSystemic risk in derivative markets: a graphtheory analysis. D. Lautier & F. Raynaud
Systemic risk in derivative markets: a graphtheory analysis D. Lautier & F. Raynaud Objectives Empirical study on systemic risk in derivative markets Integration as a necessary condition for systemic
More informationThe Geometric Structure of Spanning Trees and Applications to Multiobjective Optimization
The Geometric Structure of Spanning Trees and Applications to Multiobjective Optimization By ALLISON KELLY O HAIR SENIOR THESIS Submitted in partial satisfaction of the requirements for Highest Honors
More information