Frank a Campo

collaborators

4 papers

math.CO2025

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 $X$ , let $P (X)$ denote the set of all posets with carrier $X$ , ordered by inclusion of their partial order relations. We investigate propertie…

math.CO2025

Crowns as retracts

Frank a Campo

We investigate crowns as retracts of finite posets. We define a multigraph $F (P)$ reflecting the network of so-called improper 4-crowns contained in the extremal points…

math.CO2024

About posets of height one as retracts

Frank a Campo

We investigate connected posets $C$ of height one as retracts of finite posets $P$ . We define two multigraphs: a multigraph $F (P)$ reflecting the network of so-called im…

math.CO2024

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 $P$ , let $E (P)$ be the poset induced by the extremal points of $P$ . We show that the fixed point property of $E (P)$ implies the fixed point property of…