# Trees

• December 17th 2012, 11:43 AM
mizzlizzym
Trees
I was given the following question on an assignment and do not understand the wording of it. Can someone please clarify or simplify it so that I can attempt to solve it?

Let T1 = (V1, E1), T2 = (V2, E2) be two trees where |E1|= 17 and |V2| = 2|V1|. Determine |V1|, |V2|, and |E2|.

Thanks!
• December 17th 2012, 12:06 PM
Plato
Re: Trees
Quote:

Originally Posted by mizzlizzym
Can someone please clarify or simplify it so that I can attempt to solve it?
Let T1 = (V1, E1), T2 = (V2, E2) be two trees where |E1|= 17 and |V2| = 2|V1|. Determine |V1|, |V2|, and |E2|.

A tree is an a-cyclic connected graph. If a tree has $n$ vertices it has $n-1$ edges. You are told the number of edges in $T_1$.
• December 17th 2012, 12:59 PM
mizzlizzym
Re: Trees
In other words 18 vertices, 17 edges for T1?
• December 17th 2012, 01:05 PM
Plato
Re: Trees
Quote:

Originally Posted by mizzlizzym
In other words 18 vertices, 17 edges for T1?

YES. Now what about $T_2~?$
• December 17th 2012, 01:25 PM
mizzlizzym
Re: Trees
T1= (18,17)
V2= 2|V1|
would this mean that we multiply V1 by 2 to get V2?
V2=36 E2=35?