finite set
a set is finite iff it has cardinality 
for some broken link: blk:def-natural-set-inf ; otherwise, the set is called infinite. if 
is a finite set, we use 
to denote the cardinality of .
[cite:;taken from @tao_analysis_1 definition 3.6.10]
for some broken link: blk:def-natural-set-inf ; otherwise, the set is called infinite. if is a finite set, we use to denote the cardinality of .[cite:;taken from @tao_analysis_1 definition 3.6.10]