ThmDex – An index of mathematical definitions, results, and conjectures.

ThmDex – An index of mathematical definitions, results, and conjectures.

Result R4222 on D181: Canonical set epimorphism

Quotienting a set reduces its cardinality

Formulation 0

Let $X / {\sim} $ be a D180: Quotient set.

Then \begin{equation} |X / {\sim}| \leq |X| \end{equation}