# Determine if G and H are isomorphic

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cristo
Staff Emeritus
You must show some work before we can help. One possible approach is to work out the degree of the vertices in each graph and try to identify those in G with those in H.

You must show some work before we can help. One possible approach is to work out the degree of the vertices in each graph and try to identify those in G with those in H.

hello
thanx i know about the dgrees but i still don't know how to determine that somtime the degree fo the vertices does tell you a bout that... so i know step by step details in order to know all possiblities.... i appreciate your help
thanx

HallsofIvy
Homework Helper
Very well, do you know what "isomorphic" MEANS? Notice that cristo did not just say "work out the degree" he also said "try to identify those in G with those in H". What have you done toward that? What is the degree of each point in G and each point in H?

okey thats what i have but i still need some one to explain that in steps

For G this graph is made of
a 3-cycle agc,
a 4-cycle hdbf.
For H this graph is made of
a 7-cycle 2583647. C

so G and H are not isomorphic

i am not sure if this iright or wrong and the same time i need some explanation so i can be sure for what i am doing

thanc

cristo
Staff Emeritus
You've not answered Halls' question: what does isomorphic mean? What is the degree of each vertex of G and each vertex of H?

Also, I don't understand your notation: what, for example, does the cycle agc mean? I would presume it to mean an edge from a to g, another from g to c and a third from c to a; but there is no edge from a to g in the graph G! Please explain your notation.

Isomorphic means same shaped,,,,,,,, now i need explanation

i tried to follow some examples with no luck

cristo
Staff Emeritus
Isomorphic means same shaped,,,,,,,, now i need explanation

i tried to follow some examples with no luck

You need to be more precise-- "same shaped" is not a mathematical definition of two isomorphic graphs.

Have you read the rest of my last post? Please answer my questions-- I will not tell you the answer without you putting some effort into solving the problem.

You need to be more precise-- "same shaped" is not a mathematical definition of two isomorphic graphs.

Have you read the rest of my last post? Please answer my questions-- I will not tell you the answer without you putting some effort into solving the problem.

isomorphic:

Two graphs are isomorphic if there is a one-to-one correspondence between their vertices and there is an edge between two vertices of one graph if and only if there is an edge between the two corresponding vertices in the other graph.

G:

a-5 degrees
b-5
.

.
h- 5

for
H:

1-6 DEGREES
2-4
3-5
4-5
...
,,,
8-5 DEGREES