Universal analytic preorders arising from surjective functions
Tom 187 / 2005
Fundamenta Mathematicae 187 (2005), 193-212
MSC: 03E15, 54F15.
DOI: 10.4064/fm187-3-1
Streszczenie
Examples are presented of $ {\bf\Sigma}_1^1$-universal preorders arising by requiring the existence of particular surjective functions. These are: the relation of epimorphism between countable graphs; the relation of being a continuous image (or a continuous image of some specific kind) for continua; the relation of being continuous open image for dendrites.
