Ring isomorphisms and pentagon subspace lattices Original Research Article

If K, L and M are (closed) subspaces of a Banach space X satisfying K∩M=(0), Klogical orL=X and Lsubset ofM, then image is called a pentagon subspace lattice on X. Let image be a pentagon subspace lattice on a complex Banach space Xi, for i=1, 2. Then every ring isomorphism from image onto image is a quasi-spatially induced linear or conjugate-linear algebra isomorphism.