
A space \(X\) is strongly dominated by a space \(Y\) if there exists a continuous surjection \(f:Y \to X\) and a compact cover \(\mathcal F\) of \(X\) such that for any compact set \(E\subset X\), there is a compact set \(K\subset Y\) with \(E\subset f(K)\). Answering a question from [\textit{D. Guerrero Sánchez} and the author, J. Math. Anal. Appl. 454, No. 2, 533--541 (2017; Zbl 1394.54001)], the author proves that if \(X\) is a Lindelöf \(\Sigma\)-space and the function space \(C_p(X,[0,1])\) is strongly dominated by a second countable space, then \(X\) is countable. On the other hand, Martin's Axiom MA implies the existence of a countable space \(Z\) strongly dominating \(C_p(X)\) for an uncountable space \(X\). Also, assuming MA, strong domination by a countable space of \((X \times X) \setminus \Delta_X\) for a compact space \(X\) need not imply metrizability of \(X\). Twelve interesting open problems are posed.
Function spaces in general topology, function space, Martin's Axiom, complement of the diagonal, Continuous maps, Lindelöf \(\Sigma\)-space, countable space, Compactness in topological linear spaces; angelic spaces, etc., strong domination
Function spaces in general topology, function space, Martin's Axiom, complement of the diagonal, Continuous maps, Lindelöf \(\Sigma\)-space, countable space, Compactness in topological linear spaces; angelic spaces, etc., strong domination
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