South-West University "Neofit Rilski"

output

20082026

most citedUnstable states in dissociation of relativistic nuclei. Recent findings and prospects of researches

16 citations

researchers with a paper here

Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.

collaborating institutions

Showing math.RAShow all

13 papers · 1 filter

math.RA2025

On certain subsemigroups of finite oriented and order-decreasing full transformations

Gonca Ayık, Hayrullah Ayık, Ilinka Dimitrova +1

Let $O RD_{n}$ be the semigroup consisting of all oriented and order-decreasing full transformations on the finite chain $X_{n} = {1 < \dots < n}$ , and for $1\leq r\leq n-1…

math.RA2024

Presentations for monoids of partial endomorphisms of a star graph

Ilinka Dimitrova, Vítor H. Fernandes, Jörg Koppitz

In this paper, we consider the monoids of all partial endomorphisms, of all partial weak endomorphisms, of all injective partial endomorphisms, of all partial strong endomorphisms…

math.RA2023★ 1 cited

Presentations for three remarkable submonoids of the dihedral inverse monoid on a finite set

Ilinka Dimitrova, Vítor H. Fernandes, Jörg Koppitz +1

In this paper we consider the submonoids $O PD I_{n}$ , $M D I_{n}$ and $O D I_{n}$ of the dihedral inverse monoid $D I_{n}$ of all orientation-preserving,…

math.RA2022

The rank of the inverse semigroup of all partial automorphisms on a finite crown

Ilinka Dimitrova, Jörg Koppitz

For $n \in N$ , let $[n] = {1, 2, \dots, n}$ be an $n$ - element set. As usual, we denote by $I_{n}$ the symmetric inverse semigroup on $[n]$ , i.e. the partial one-to-one…

math.RA2021★ 13 cited

On the semigroup of all partial fence-preserving injections on a finite set

Ilinka Dimitrova, Jörg Koppitz

For $n \in N$ , let $X_{n} = {a_{1}, a_{2}, \dots, a_{n}}$ be an $n$ - element set and let $F = (X_{n}; <_{f})$ be a fence, also called a zigzag poset. As usual, we denote…

math.RA2021★ 2 cited

On relative ranks of the semigroup of orientation-preserving transformations on infinite chain with restricted range

Ilinka Dimitrova, Jörg Koppitz

Let $X$ be an infinite linearly ordered set and let $Y$ be a nonempty subset of $X$ . We calculate the relative rank of the semigroup $O P (X, Y)$ of all orientation-preserving transfo…

math.RA2021

Partial Automorphisms and Injective Partial Endomorphisms of a Finite Undirected Path

Ilinka Dimitrova, Vítor H. Fernandes, Jörg Koppitz +1

In this paper, we study partial automorphisms and, more generally, injective partial endomorphisms of a finite undirected path from Semigroup Theory perspective. Our main objective…

math.RA2020★ 3 cited

On relative ranks of finite transformation semigroups with restricted range

Ilinka Dimitrova, Jörg Koppitz

In this paper, we determine the relative rank of the semigroup $T (X, Y)$ of all transformations on a finite chain $X$ with restricted range $Y \subseteq X$ modulo the set $O P (X, Y)$ …

math.RA2020★ 2 cited

On Relative Ranks of the Semigroup of Orientation-preserving Transformations on Infinite Chains

Ilinka Dimitrova, Jörg Koppitz

In this paper, we determine the relative rank of the semigroup OP(X) of all orientation-preserving transformations on infinite chains modulo the semigroup O(X) of all order-preserv…

math.RA2018★ 10 cited

Ranks of monoids of endomorphisms of a finite undirected path

Ilinka Dimitrova, Vítor H. Fernandes, Jörg Koppitz +1

In this paper we study the widely considered endomorphisms and weak endomorphisms of a finite undirected path from monoid generators perspective. Our main aim is to determine the r…

math.RA2015★ 8 cited

A note on generators of the endomorphism semigroup of an infinite countable chain

Ilinka Dimitrova, Vítor H. Fernandes, Jörg Koppitz

In this note, we consider the semigroup $O (X)$ of all order endomorphisms of an infinite chain $X$ and the subset $J$ of $O (X)$ of all transformations $α$ such that $∣ I m (α) ∣ = ∣ X ∣$ .…

math.RA2012

Stable varieties of semigroups and groupoids

Sl. Shtrakov, J. Koppitz

The paper deals with $Σ -$ composition and $Σ$ -essential composition of terms, which lead to stable and s-stable varieties of algebras. A full description of all stable varieties of…

math.RA2008★ 1 cited

Multi-Hypersubstitutions and Colored Solid Varieties

Klaus Denecke, Jorg Koppitz, Slavcho Shtrakov

Hypersubstitutions are mappings which map operation symbols to terms. Terms can be visualized by trees. Hypersubstitutions can be extended to mappings defined on sets of trees. The…