Examples are presented of $ oldsymbol 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.

Universal analytic preorders arising from surjective functions

CAMERLO, RICCARDO
2005-01-01

Abstract

Examples are presented of $ oldsymbol 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.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/948665
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