A 2-form between two sup-lattices L and R is defined to be a sup-lattice
bimorphism L x R -> 2. Such 2-forms are equivalent to Galois connections, and
we study them and their relation to quantales, involutive quantales and
quantale modules. As examples we describe applications to C*-algebras.Comment: 30 pages. Contains more detailed background section and corrections
of several typos and mistake