5 citations · 11 across the 11 of their papers we have counts for
13 papers
About posets of height one as retracts
Frank a Campo
We investigate connected posets of height one as retracts of finite posets . We define two multigraphs: a multigraph reflecting the network of so-called im…
A Flexible Approach for the Enumeration of Down-Sets and its Application on Dedekind Numbers
Frank a Campo
We introduce a flexible approach for the enumeration of the down-sets of a finite poset and test it with the calculation of the Dedekind numbers and .…
Crowns as retracts
Frank a Campo
We investigate crowns as retracts of finite posets. We define a multigraph reflecting the network of so-called improper 4-crowns contained in the extremal points…
About posets for which no lower cover or no upper cover has the fixed point property
Frank a Campo
For a finite non-empty set , let denote the set of all posets with carrier , ordered by inclusion of their partial order relations. We investigate propertie…
The fixed point property of a poset and the fixed point property of the poset induced by its extremal points
Frank a Campo
For a connected finite poset , let be the poset induced by the extremal points of . We show that the fixed point property of implies the fixed point property of…
A generalization of a theorem of Erné
Frank a Campo
Let be a finite set, and . Marcel Erné showed in 1981, that the number of posets on containing as an antichain equals the number of posets $…
A recursive approach for the enumeration of the homomorphisms from a poset to the chain
Frank a Campo
Let be the set of order homomorphisms from a poset to the chain . We develop a recursive approach for the calculation of the cardinality of $…
Criteria for the less-equal-relation between partial Lovász-vectors of digraphs
Frank a Campo
Finite digraphs and are studied with for every finite digraph , where is the set of order ho…
Interdependencies of less-equal-relations between partial Lovász-vectors of digraphs
Frank a Campo
For digraphs and , let be the set of all homomorphisms from to , and let be the subset of those homomorphisms mapping all proper arcs…
Strong G-schemes and strict homomorphisms
Frank a Campo
Let be a representation system of the non-isomorphic finite posets, and let be the set of order homomorphisms from to . For finite posets $R…
Calculation Rules and Cancellation Rules for Strong Hom-Schemes
Frank a Campo
Let denote the set of homomorphisms from the poset to the poset . In previous studies, the author has started to analyze what it is in the structure of finit…
Generalized One-to-One Mappings between Homomorphism Sets of Digraphs
Frank a Campo
Structural properties of finite digraphs and are studied which enforce for every finite digraph , where ${\c…
Exponential functions of finite posets and the number of extensions with a fixed set of minimal points
Frank A Campo, Marcel Erné
We establish formulas for the number of all downsets (or equivalently, of all antichains) of a finite poset P. Then, using these numbers, we determine recursively and explicitly th…