4 problems

Let $X$ be a noncompact generalized continuum. Let $T$ be an infinite tree and let … be a proper embedding. Assume that the induced map on end spaces … is injective. Existence of a…

Let $Q$ be any class of morphisms of topological spaces, and write $Q^{lr}$ for its double Quillen orthogonal. The proper-map maximality conjecture. If … then … The paper proves th…

Let $f$ be a map of finite topological spaces. Say that a fibre has two points bounded above but not below when its two points have a common upper bound but no common lower bound,…

Let $\{o\}\to\{o\to c\}$ be the indicated map of finite topological spaces, and let the subscript $<5$ denote the subclass consisting of maps between spaces with fewer than $5$ poi…