English

On binary relations without non-identical endomorphisms

Logic 2007-05-23 v3 Combinatorics

Abstract

On every set A there is a rigid binary relation, i.e. such a relation R that there is no homomorphism (A,R)->(A,R) except the identity (Vopenka et al. [1965]). We state two conjectures which strengthen this theorem. We prove these conjectures for some cardinalities.

Cite

@article{arxiv.math/0003181,
  title  = {On binary relations without non-identical endomorphisms},
  author = {Apoloniusz Tyszka},
  journal= {arXiv preprint arXiv:math/0003181},
  year   = {2007}
}

Comments

3rd version, minor changes, PostScript, submitted to Aequationes Math