Let F be a family of sets in Rd (always d≥2). A set M⊂Rd is called F-convex, if for any pair distinct points x,y∈M, there F∈F, such that x,y∈F and F⊂M. four {w,x,y,z}⊂Rd rectangular quadruple, conv{w,x,y,z} non-degenerate rectangle. If the all quadruples, then we obtain right quadruple convexity, abbreviated as rq-convexity. In this paper focus on rq-convexity complements, taken most cases ball...

We show that the fundamental group of a prime alternating surfacearc complement is δ-hyperbolic in case the genus of the surface is greater than zero. AMS Subject classification: 57M25, 57M50, 57M05

It is know in topos theory that axiom of choice implies that the topos is Boolean. In this paper we want to prove and generalize this result in the context of allegories. In particular, we will show that partial identities do have complements in distributive allegories with relational sums and total splittings assuming the axiom of choice. Furthermore, we will discuss possible modifications of ...

Ever since Corlett and Hague (1953), it has been understood that it tends to be optimal on second-best grounds to (relatively) tax complements to leisure and subsidize substitutes because doing so helps to offset the distorting effect of taxation on labor supply. Yet in the context of simultaneous optimization of a nonlinear income tax and commodity taxes, Atkinson and Stiglitz (1976) claim to ...