#Inclusion-Exclusion

3 posts

Number Theory #3 April 28, 2026 5 min read

From Eratosthenes to Möbius Inclusion-Exclusion

Eratosthenes sieve for μ; g/f/h framework; Conclusions 1 and 2 with derivations and tables; GCD table intuition; CF 803F Coprime Subsequences with bottom-up and Möbius approaches.

#math #number-theory #mobius #sieve #inclusion-exclusion

Combinatorics D1 April 24, 2026 13 min read

Diophantine Equations

Stars and bars, bounded Diophantine equations via inclusion-exclusion, prefix-sum DP, D&C NTT, equal-cap formula, and a full worked example on CF 2127F.

#math #combinatorics #diophantine #stars-and-bars #inclusion-exclusion

Combinatorics #1.2 April 20, 2026 2 min read

Inclusion-Exclusion, Bounded Diophantine Equations, and Derangements

Inclusion-exclusion in set and operator form, equal-count subproblems, bounded Diophantine counting, derangements, Stirling numbers, and selected contest problems.

#math #combinatorics #inclusion-exclusion #derangements #diophantine