Proving the Existence of a Maximum-Edge Vertex in Acyclic Tournament Graphs

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Homework Help Overview

The problem involves proving the existence of a unique vertex in an acyclic tournament graph that has more directed edges than any other vertex. The context is within graph theory, specifically focusing on directed graphs and properties of tournament graphs.

Discussion Character

  • Conceptual clarification, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to explore the proof by contradiction and questions whether this is a suitable approach. They also discuss the properties of acyclic graphs and the implications for vertex relationships.
  • Some participants question the nature of edges in tournament graphs, particularly how vertices can have differing numbers of edges given the complete graph structure.
  • Clarification is sought regarding the definition of edges in the context of directed graphs and indegree.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem and the properties of tournament graphs. There is no explicit consensus yet, but there are productive inquiries into the nature of the edges and the proof approach.

Contextual Notes

Participants are navigating assumptions about the properties of acyclic tournament graphs and the definitions of edges in directed graphs. There is a mention of potential misunderstandings regarding the nature of edges in complete graphs versus directed graphs.

njama
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Homework Statement



Prove the following:

If the tournament graph is acyclic, there is exactly one vertex which got edges more than any vertex in the graph.

Homework Equations



A tournament is a directed graph (digraph) obtained by assigning a direction for each edge in an undirected complete graph


The Attempt at a Solution



I am not sure how to start. Is it easier to go with the indirect proof (i.e proof by contradiction) ?

Lets say that that kind of vertex does not exist. Than either all vertices have equal number of edges or there are two edges or more with same number of edges which got more edges than any other pair of vertices.

Because the graph is acyclic we could easily see that the relation under the graph is not transitive, not symmetric, not reflexive, is asymmetric.

Could somebody help me please and tell me if I should prove like the way I did?

Thank you.
 
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any ideas please?
 
Question: If a tournament graph is simply a complete graph with directions assigned to each edge, how can any vertex in a tournament graph have more edges than the others? In a complete graph every vertex "has" the same number of edges.
 
Sorry for misunderstanding but I meant starting edges (directed graph) or vertex with max indegree.

Thank you.
 

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