Let G be a simple undirected graph with n vertices where n is an
even number....
Let G be a simple undirected graph with n vertices where n is an
even number. Prove that G contains a triangle if it has at least
(n^2 / 4) + 1 edges using mathematical induction.
Let G(V, E,w) be a weighted undirected graph, where V is the set
of vertices, E is the set of edges, and w : E → R + is the weight
of the edges (R + is the set of real positive numbers). Suppose
T(G) is the set of all minimum spanning trees of G and is
non-empty. If we know that the weight function w is a injection,
i.e., no two edges in G have the same weight, then:...
Given an undirected graph G = (V,E),
consisting of n vertices and m edges, with each
edge labeled from the set {0,1}.
Describe and analyze the worst-case time complexity of an
efficient algorithm to find any cycle consisting of edges whose
labels alternate 0,1.
let
G be a simple graph. show that the relation R on the set of
vertices of G such that URV if and only if there is an edge
associated with (u,v) is a symmetric irreflexive relation on
G
Let Kn denote the simple graph on n vertices.
(a) Let v be some vertex of Kn and consider K n −
v, the graph obtained by deleting
v. Prove that K n − v is isomorphic to K n−1 .
(b) Use mathematical induction on n to prove the following
statement:
K n , the complete graph on n vertices, has
n(n-1)/2
edges
Consider an undirected graph G that has n distinct
vertices. Assume n≥3.
How many distinct edges will there be in any circuit for G that
contains all the vertices in G?
What is the maximum degree that any vertex in G can have?
What is the maximum number of distinct edges G can have?
What is the maximum number of distinct edges that G can have if
G is disconnected?
Let Q:= {1,2,...,q}. Let G be a graph with the elements of Q^n
as vertices and an edge between (a1,a2,...,an) and (b1,b2,...bn) if
and only if ai is not equal to bi for exactly one value of i. Show
that G is Hamiltonian.
Let G be a bipartite graph with 107 left vertices and 20 right
vertices. Two vertices u, v are called twins if the set of
neighbors of u equals the set of neighbors of v (triplets,
quadruplets etc are defined similarly).
Show that G has twins.
Bonus: Show that G has triplets. What about quadruplets, etc.?
(a) What is the maximum degree of a vertex in a simple graph
with n vertices?
(b) What is the maximum number of edges in a simple graph of
n vertices?
(c) Given a natural number n, does there exist a simple
graph with n vertices and the maximum number of edges?
13.6 Let G be a simple connected cubic plane graph, and let pk
be the number of k-sided faces. By counting the number of vertices
and edges of G, prove that
3p3 + 2p4 + p5 - c7 - 2p8 - • • • = 12.
Deduce that G has at least one face bounded by at most five
edges.