KEY WORDS
Graphs and Digraphs Dominance Digraphs Communication Digraphs Networks
graph theory
graph
vertex
edge
directed edge
directed graph
digraph
adjacency matrix
dominance
asymmetric matrix
communication digraph
symmetric matrix
organizational communication
   digraph
path
connected digraph
network
cycle
tree
spanning tree
minimum spanning tree

Review Exercises

Write a matrix for each graph that is a digraph. Identify any adjacency matrices.
1. 2. 3. 4.
Sketch a digraph for each of the following matrices.
5.
A B C
A
B
C
6.
M N P
M
N
P
7.
R S T V
R
S
T
V
8.
X Y Z W
X
Y
Z
W
For each matrix n Exercise 9-14 that is the matrix of a dominance digraph, find the matrix representing two-stage dominance. Find the total umber of vertices dominated by each vertex in one or two stages.
9.
A B C
A
B
C
10.
M N P
M
N
P
11.
X Y Z
X
Y
Z
12.
R S T
R
S
T
13.
P Q R S
P
Q
R
S
14.
A B C D
A
B
C
D
Write the corresponding matrix for each digraph. Find the number of two-stage dominances for A, B, C, and D.
15. 16.
Decide on the winner of each of the following tournaments, using one- or two-stage dominances. Here AB means a game between teams A and B.
17.
Game AB AC AD AE BC BD BE CD CE DE
Winner A C D A B B B D C D
 
18.
Game AB AC AD AE BC BD BE CD CE DE
Winner A A D A B B B D C E
 
Write the associated matrix for each digraph. Identify any communication digraph or organizational communication digraphs.
19.   20.   21.   22.  
Sketch a digraph for each matrix of a communication digraph. Find all two-stage paths of communication.
23. 24. 25. 26.
Identify all paths from A to D in following digraphs.
27.   28.  
Show that each of the following digraphs is connected.
29.   30.  
Identify all cycles in the following networks.
31.   32.  
Find all spanning trees for each network
33.   34.  
Find a minimum spanning tree for each network.
35.   36.  

 



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