Prove that for n ⩾ 2 there are exactly two n-vertex graphs with
n − 1...
Prove that for n ⩾ 2 there are exactly two n-vertex graphs with
n − 1 distinct degrees (up to isomorphism). The other answers on
the website are incorrect.
Prove that 1^3 + 2^3 + · · · + n^3 = (1 + 2 + · · · + n)^2 for
every n ∈ N. That is, the sum of the first n perfect cubes is the
square of the sum of the first n natural numbers. (As a student, I
found it very surprising that the sum of the first n perfect cubes
was always a perfect square at all.)
1.Prove that{2k+1:k∈N}∩{2k2 :k∈N}=∅.
2.Give two examples of ordered sets where the meaning of ” ≤ ”
is not the same as the one used with the set of real numbers R.