Documentation

Newtype wraper which captures Boolean ring structure, which holds for every Heyting algebra. A Boolean ring is a ring which satisfies:

a <.> a = a

Some other properties:

a <+> a = mempty                  -- thus it is a ring of characteristic 2

a <.> b = b <.> a                 -- hence it is a commutative ring

a <+> (b <+> c) = (a <+> b) <+> c -- multiplicative associativity

Alias for mappend.