-Polaren in halbgeordneten Mengen
Martin's axiom and partitions
Maximal antichains in a partially ordered set
Maximal subsemilattices of the full transformation semigroup on a finite set [Book]
Measurability of functions with values in partially ordered spaces
Measurable spaces with c.c.c. [Book]
Methods of calculating cohomological and Hochschild-Mitchell dimensions of finite partially ordered sets.
Möbius inversion for the Bruhat ordering on a Weyl group
Modular ordered sets
Modular posets and semigroups.
Modulare Inzidenzstrukturen
More on the complexity of cover graphs
In response to [3] and [4] we prove that the recognition of cover graphs of finite posets is an NP-hard problem.
More set-theory around the weak Freese–Nation property
We introduce a very weak version of the square principle which may hold even under failure of the generalized continuum hypothesis. Under this weak square principle, we give a new characterization (Theorem 10) of partial orderings with κ-Freese-Nation property (see below for the definition). The characterization is not a ZFC theorem: assuming Chang’s Conjecture for , we can find a counter-example to the characterization (Theorem 12). We then show that, in the model obtained by adding Cohen reals,...
Multiabbildungen und Anordnungen der Mengen