Proof of orthogonality of binomial coefficients
42606
Orthogonality for Binomial Coefficients
144571
A conjecture including binomial coefficients
111951
Prove $\binom{n}{m}\binom{m}{k} = \binom{n}{k}\binom{n-k}{m-k}$
28936
Proving equation with binomial coefficient
118674
Simple upper bound for $\binom{n}{k}$
84522
A better proof for $\det(P) = \pm1$ if $P$ is an orthogonal matrix
67844
Prove equation with binomial coefficient
26801
Show that orthogonal matrices are diagonalizable
35625
Direct sum of orthogonal subspaces
91648
Binomial coefficient proof
118372
Combination proof for $n(n+1)2^{n-2}=\sum_{k=1}^{n}k^2\binom{n}{k}$
107810
Induction with Binomial Coefficients
31196
Prove $\binom{n}{a}\binom{n-a}{b-a} = \binom{n}{b}\binom{b}{a}$
29828
Combinatorial proof of $\sum^{n}_{i=1}\binom{n}{i}i=n2^{n-1}$.
129304
Alternative combinatorial proof for $\sum\limits_{r=0}^n\binom{n}{r}\binom{m+r}{n}=\sum\limits_{r=0}^n\binom{n}{r}\binom{m}{r}2^r$
4610
Proving an identity with a combinatorial proof: $\binom{n}{k}\binom{k}{r}=\binom{n}{r}\binom{n-r}{k-r}$
109576
Prove that $\binom{m+n}{m}=\sum\limits_{i=0}^m \binom{m}{i}\binom{n}{i}$