KnownDomain -- an option used to specify to certain functions that we know that the ring is a domain

If true, then some functions will not check whether or not the ring is domain, they will assume it and proceed.

Functions with optional argument named KnownDomain:

• dualize(...,KnownDomain=>...) -- see dualize -- finds an ideal or module isomorphic to Hom(M, R)
• reflexify(...,KnownDomain=>...) -- see reflexify -- calculate the double dual of an ideal or module Hom(Hom(M, R), R)
• torsionSubmodule(...,KnownDomain=>...) -- see torsionSubmodule -- create the torsion submodule of a module