Characterizing Possible Sequences for Forests | Graph Theory Homework Question

[roadrunner]

Homework Statement

Characterize all possible sequences d1; d2; : : : ; dn so that there exists a forest
with vertex set fv1; v2; : : : vng with deg(vi) = di. (So, you should nd a statement of the
form: a sequence d1; : : : dn comes from a forest if and only if ... )


I emailed him and asked...he said this

In the last homework, you proved that a sequence d1, d2, .. dn is the
degree sequence of a tree if and only if d1..dn are positive integers
and they sum to 2n-2.

I want you to prove a similar thing for forests. So you should show that
a sequence d1, d2, .. dn is the degree sequence of a tree if and only if

The Attempt at a Solution

Not too sure what I need to do?

 

[roadrunner]

bump?