Complex sentence: The total number of elements in a multiset, including repeated memberships, is the cardinality of the multiset, and the number of times an element belongs to the multiset is the multiplicity of that member.
Split into simpler sentences: The total number of elements in a multiset, including repeated memberships, is the cardinality of the multiset. The number of times an element belongs to the multiset is the multiplicity of that member.