Section 26
Modular arithmetic
Modular congruence
intermedioviz
Defines equality of remainders modulo n.
Modular operations
intermedioviz
Congruences are preserved under addition and multiplication.
Modular inverse
intermedioviz
The inverse exists exactly when a and n are coprime.
Bézout's identity
intermedio
Connects the greatest common divisor with integer linear combinations.
Chinese remainder theorem
avanzadoviz
Systems with pairwise coprime moduli have a unique solution modulo N.
Fermat's little theorem
avanzadoviz
Central result for modular arithmetic and cryptography.