Preprints (rote Reihe) des Fachbereich Mathematik
- yes (3) (remove)
- Hyperquasivarieties (2003)
- We consider the notion of hyper-quasi-identities and hyperquasivarieties, as a common generalization of the concept of quasi-identity and quasivariety invented by A.I. Mal'cev, cf. , cf.  and hypervariety invented by the authors in .
- Locally Maximal Clones II (1999)
- Clones preserving a quasi-order (1999)
- It is proved that if a finite non-trivial quasi-order is nota linear order then there exist continuum many clones, whichconsist of functions preserving the quasi-order and containall unary functions with this property. It is shown that, fora linear order on a three-element set, there are only 7 suchclones