Hand-Shaking Theorem Part-1

Duration: 5 min

This video lesson is available to enrolled students.

Return to /learn/BIHAR-POLYTECHNIC-LECTURER-COMPUTER-SCIENCE/paper-1-discrete-structures-and-theory-of-logic/graph-theory/degree-of-vertex-isolated-and-pendant-vertices-handshaking-lemma-and-degree-sequence/asset-hand-shaking-theorem-part-1 after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. Discrete Mathematics: Permutation, Combination and Probability / क्रमचय, संचय एवं प्रायिकता, Set Theory, Relations, Functions, Propositional and Predicate Logic, Graph Theory, Group Theory
  2. Digital Logic: Digital Systems & Boolean Basics, Boolean Expression, Boolean Minimization, Logic Gates & Hardware, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep
  3. Computer Organization and Architecture: Basics of COA, Programming the Basic Computer, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Pipelining, Multiprocessors
  4. Programming: Language Design, C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++
  5. Data Structures: Introduction to DS, Array, Linked List, Stack, Queue, Tree, Graphs, Hashing
  6. Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  7. Theory of Computation: Grammar, Regular Language Properties, Moore & Mealy Machines, Turing Machines
  8. Compiler Design: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment, Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Pushdown Automata & CFG, Complexity Theory
  9. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Security
  10. Database Management Systems: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, ORDBMS, NoSQL
  11. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a detailed explanation of the Hand-shaking theorem in graph theory. The instructor defines the theorem, which states that the sum of the degrees of all vertices in a graph is equal to twice the number of edges. He then derives a significant corollary: the number of vertices with odd degrees in any graph must always be an even number. The lesson is supported by a visual example featuring a graph with vertices labeled 'a' through 'j' and a corresponding table listing the degree of each vertex.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video begins with the definition of the Hand-shaking theorem displayed on the screen: 'Since each edge contribute two degree in the graph, the sum of the degree of all vertices in G is twice the number of edges in g.' The instructor writes the mathematical formula $\sum_{i=1}^{n} d(vi) = 2|E|$ on the whiteboard area. He explains the logic that every edge connects two vertices, contributing 1 to each, totaling 2 per edge. He underlines the summation symbol and the term $2|E|$ to emphasize the equality. He then points to the graph diagram on the left and the 'Vertex | Degree' table on the right, preparing to verify the theorem with the specific data provided.

  2. 2:00 – 5:00 02:00-05:00

    The instructor introduces a new theorem: 'The number of vertices of odd degree in a graph is always even.' He writes the equation $\sum_{i=1}^{n} d(vi) = \sum_{even} d(vi) + \sum_{odd} d(vi)$ to break down the total sum. He explains that the total sum is even (from the Hand-shaking theorem) and the sum of even degrees is inherently even. Therefore, the sum of odd degrees must also be even, which is only possible if there is an even number of odd-degree vertices. To prove this, he circles the vertices with odd degrees in the table: 'a' (1), 'b' (1), 'c' (1), 'f' (1), 'g' (3), and 'h' (3). He counts these circled entries, confirming there are exactly 6 vertices of odd degree, which satisfies the theorem.

The lecture effectively connects the abstract theorem to a concrete example. By calculating the sum of degrees (1+1+1+4+4+1+3+3+2+2 = 22) and comparing it to twice the number of edges (11 edges * 2 = 22), the instructor validates the Hand-shaking theorem. The second part of the lecture logically deduces the parity of odd-degree vertices, a fundamental result in graph theory often used to prove the existence of Eulerian paths or cycles. The visual aids, including the red checkmarks and circles, help students track the specific vertices being discussed.

Loading lesson…