A partial order where all monotone maps are definable
Tom 152 / 1997
Fundamenta Mathematicae 152 (1997), 255-265
DOI: 10.4064/fm-152-3-255-265
Streszczenie
It is consistent that there is a partial order (P,≤) of size $ℵ_1$ such that every monotone function f:P → P is first order definable in (P,≤).