Isomorphisms and Isometric Multipliers

Isometric Isomorphisms of Measure Algebras

C∗-Isomorphisms, Jordan Isomorphisms, and Numerical Range Preserving Maps

Let V = B(H) or S(H), where B(H) is the algebra of bounded linear operator acting on the Hilbert space H, and S(H) is the set of self-adjoint operators in B(H). Denote the numerical range of A ∈ B(H) by W (A) = {(Ax, x) : x ∈ H, (x, x) = 1}. It is shown that a surjective map φ : V→ V satisfies W (AB +BA) =W (φ(A)φ(B) + φ(B)φ(A)) for all A,B ∈ V if and only if there is a unitary operator U ∈ B(H...

Group Homomorphisms and Isomorphisms

c W W L Chen, 1991, 1993, 2013. This chapter is available free to all individuals, on the understanding that it is not to be used for financial gain, and may be downloaded and/or photocopied, with or without permission from the author. However, this document may not be kept on any information storage and retrieval system without permission from the author, unless such system is not accessible t...

Randomized Reductions and Isomorphisms

Randomizing reductions have provided new techniques for tackling average-case complexity problems. For example, although some NP-complete problems with uniform distributions on instances cannot be complete under deterministic one-one reductions [WB95], they are complete under randomized reductions [VL88]. We study randomized reductions in this paper on reductions that are one-one and honest map...

Homomorphisms and Isomorphisms

If (G, *) and (H, •) are groups, then a function f : G −→ H is a homomorphism if f (x * y) = f (x) • f (y) for all x, y ∈ G. Example: Let (G, *) be an arbitrary group and H = {e}, then the function f : G −→ H such that f (x) = e for any x ∈ G is a homomorphism. In fact, f (x * y) = e = e • e = f (x) • f (y). f (x) = x for any x ∈ G is a homomorphism. In fact, f (x * y) = x * y = f (x) * f (y). ...