User blog comment:Rgetar/Help to name function/@comment-30754445-20180423200016/@comment-32213734-20180424205105

PsiCubed2, thank you!

Also I was thinking about short name for this function. I read Wikipedia article Cardinality, and it says: "The cardinality of a set A is usually denoted |A|, with a vertical bar on each side; this is the same notation as absolute value and the meaning depends on context. Alternatively, the cardinality of a set A may be denoted by n(A), A, card(A), or # A." I like designation "card(A)", since it is unlikely to be confused with something else.

I probably was confused since 2ω = ω ≠ 2&#8207;1ב = &#8207;0א. As I now understand, this is not due ω ≠ &#8207;0א (actually ω = &#8207;0א), but since these are two different operations and two different arithmetics.