-vectors, Eulerian polynomials and stable polytopes of graphs.
Homotopy and homology of finite lattices.
Ideals in distributive posets
We prove that any ideal in a distributive (relative to a certain completion) poset is an intersection of prime ideals. Besides that, we give a characterization of n-normal meet semilattices with zero, thus generalizing a known result for lattices with zero.
Incidence algebras and algebraic fundamental group.
Isomorphismus der Kardinalpotenzen
Isotone analogs of results by Mal'tsev and Rosenberg.
Monotone and cone preserving mappings on posets
We define several sorts of mappings on a poset like monotone, strictly monotone, upper cone preserving and variants of these. Our aim is to study in which posets some of these mappings coincide. We define special mappings determined by two elements and investigate when these are strictly monotone or upper cone preserving. If the considered poset is a semilattice then its monotone mappings coincide with semilattice homomorphisms if and only if the poset is a chain. Similarly, we study posets which...
On incidence algebras and directed graphs.
On n-normal posets
A poset Q is called n-normal, if its every prime ideal contains at most n minimal prime ideals. In this paper, using the prime ideal theorem for finite ideal distributive posets, some properties and characterizations of n-normal posets are obtained.
On some topologies on products of ordered sets
On the power of ordered sets
Optimal decision trees on simplicial complexes.
Orthomodular Posets Can Be Organized as Conditionally Residuated Structures
It is proved that orthomodular posets are in a natural one-to-one correspondence with certain residuated structures.
Poset homology of Rees products, and -Eulerian polynomials.
Primeness and semiprimeness in posets
The concept of a semiprime ideal in a poset is introduced. Characterizations of semiprime ideals in a poset as well as characterizations of a semiprime ideal to be prime in are obtained in terms of meet-irreducible elements of the lattice of ideals of and in terms of maximality of ideals. Also, prime ideals in a poset are characterized.
Pseudocomplemented and Stone Posets
We show that every pseudocomplemented poset can be equivalently expressed as a certain algebra where the operation of pseudocomplementation can be characterized by means of remaining two operations which are binary and nullary. Similar characterization is presented for Stone posets.
Realization of posets.
Relatively pseudocomplemented posets
We extend the notion of a relatively pseudocomplemented meet-semilattice to arbitrary posets. We show some properties of the binary operation of relative pseudocomplementation and provide some corresponding characterizations. We show that relatively pseudocomplemented posets satisfying a certain simple identity in two variables are join-semilattices. Finally, we show that every relatively pseudocomplemented poset is distributive and that the converse holds for posets satisfying the ascending chain...
Residuation in twist products and pseudo-Kleene posets
M. Busaniche, R. Cignoli (2014), C. Tsinakis and A. M. Wille (2006) showed that every residuated lattice induces a residuation on its full twist product. For their construction they used also lattice operations. We generalize this problem to left-residuated groupoids which need not be lattice-ordered. Hence, we cannot use the same construction for the full twist product. We present another appropriate construction which, however, does not preserve commutativity and associativity of multiplication....
Sets and Posets with Inversions