出典:Wikipedia
出典:『Wikipedia』 (2011/06/17 17:29 UTC 版)
In mathematics a field of sets is a pair
where X is a set and
is an algebra over X i.e., a non-empty subset of the power set of X closed under the intersection and union of pairs of sets and under complements of individual sets. In other words
forms a subalgebra of the power set Boolean algebra of X. (Many authors refer to
itself as a field of sets. The word "field" in "field of sets" is not used with the meaning of field from field theory.) Elements of X are called points and those of
are called complexes.