An R-module M is called epi-retractable if every submodule of MR is a homomorphic image of M. It is shown that if R is a right perfect ring, then every projective slightly compressible module MR is epi-retractable. If R is a Noetherian ring, then every epi-retractable right R-module has direct sum of uniform submodules. If endomorphism ring of a module MR is von-Neumann regular, then M is semi-...

The uniform box product was introduced by Scott Williams in 2001, but very little was done with it until the recent (2010 and 2012) [B1], [H1] dissertations of Jocelyn Bell and Jeffrey Hankins. Their results had to do with two questions that Williams posed a decade earlier: whether the uniform box product of compact spaces is normal, and whether it is paracompact. Hankins answered the latter qu...

In the present paper for two $mathfrak{A}$-module Banach algebras $A$ and $B$, we investigate relations between $varphi$-$mathfrak{A}$-module approximate amenability of $A$, $psi$-$mathfrak{A}$-module approximate amenability of $B$, and $varphioplus psi$-$mathfrak{A}$-module approximate amenability of $Aoplus B$ ($l^1$-direct sum of $A$ and $B$), where $varphiin$ Hom$_{mathfrak{A}}(A)$ and $psi...

The Fréchet distance is a distance measure for parameterized curves or surfaces. Using a discrete approximation, we show that for triangulated surfaces it is upper semi-computable, i.e., there is a non-halting Turing machine which produces a monotone decreasing sequence of rationals converging to the result. It follows that the decision problem, whether the Fréchet distance of two given surface...