On a Putnam's 2009 problem
108321
On the problem $1$ of Putnam $2009$
121732
Functional completeness of $\{\text{or},\text{ xor}, \text{ xnor}\}$
144571
A conjecture including binomial coefficients
24924
Computing an infinite product
134440
An unexpected application of non-trivial combinatorics
7919
The pigeonhole principle - how to solve questions like that?
128032
Solving SAT by converting to disjunctive normal form
118189
Proving the pairing axiom from the rest of ZF
26212
The $1997$ IIT JEE problem
95103
A rational matrix such that $A^{2017}=I_n$
40397
P = NP and current cryptographic systems
61635
Proving AM-GM with induction
138178
Proving the number of iterations in the Euclidean algorithm
34592
Putnam 1990 A1 Induction Help
34493
Concrete Mathematics - The Josephus Problem
156408
Putnam and Beyond AM-GM help
91281
Proving the so-called "Well Ordering Principle"