19 Jan
2009
19 Jan
'09
9:40 p.m.
G'day all.
Quoting David Menendez
Are there any instances of Boolean that aren't isomorphic to Bool?
Sure. Two obvious examples: - The lattice of subsets of a "universe" set, where "or" is union "and" is intersection and "not" is complement with respect to the universe. - Many-valued logic systems. - Intuitionistic logic systems. - The "truth values" of an arbitrary topos (i.e. the points of the subobject classifier). Look up "Heyting algebra" for examples. Cheers, Andrew Bromage