Examples are presented of $ \boldsymbol \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.
|Titolo:||Universal analytic preorders arising from surjective functions|
|Data di pubblicazione:||2005|
|Appare nelle tipologie:||1.1 Articolo in rivista|