Addition and "subtraction" of polytopes
5738
Cancellation of addition on convex sets
143540
How to prove this decomposition of sum of squares?
64803
Counting two ways, $\sum \binom{n}{k} \binom{m}{n-k} = \binom{n+m}{n}$
36388
How to derive this Combinatorial identity
65983
Combinatorial proof of binomial coefficient summation identity
3392
Sum of products of elements of nonempty subsets of A set
153769
Numbers that can be expressed as the sum of two cubes in exactly two different ways
125401
Mathematical Induction: Sum of first n odd perfect cubes
142978
combinatorics: sum of product of integer compositions
131080
Geometric representation of the sum of a Geometric Series
8806
Summation of binomial coefficients
114297
Extremizing sum and difference of lengths using triangle inequality
81649
Subtract matrix of n,k dimensions from array of matrices of n,k dimensions
111954
Computing the cardinality of a combinatorial set
54198
algebra - matrices and polynoms
53244
Prove that $p \in \mathbb{R}[x]$ can be represented as a sum of squares of polynomials from $\mathbb{R}[x]$
107964
Simple combinatorics problem.