Simona Boyadzhiyska

activity

20202026

collaborators

11 papers

math.CO2026

Rainbow connecting $2$ -colorings of super-Dirac graphs

János Barát, Simona Boyadzhiyska, Andrea Freschi

Let $G$ be a graph with minimum degree $δ (G) \geq ∣ V (G) ∣/2$ . Can we color the edges of $G$ with red and blue so that every pair of non-adjacent vertices is connected by a path consist…

math.CO2025

Almost-perfect colorful matchings in three-edge-colored bipartite graphs

Simona Boyadzhiyska, Micha Christoph, Tibor Szabó

We prove that, for positive integers $n, a_{1}, a_{2}, a_{3}$ satisfying $a_{1} + a_{2} + a_{3} = n - 1$ , it holds that any bipartite graph $G$ which is the union of three perfect matchings $M_{1}$ , $M…

math.CO2024

Simultaneous edge-colourings

Simona Boyadzhiyska, Richard Lang, Allan Lo +1

We study a generalisation of Vizing's theorem, where the goal is to simultaneously colour the edges of graphs $G_{1}, \dots, G_{k}$ with few colours. We obtain asymptotically optimal bou…

math.CO2024

Odd-Ramsey numbers of complete bipartite graphs

Simona Boyadzhiyska, Shagnik Das, Thomas Lesgourgues +1

In his study of graph codes, Alon introduced the concept of the odd-Ramsey number of a family of graphs $H$ in $K_{n}$ , defined as the minimum number of colours needed to c…

math.CO2024

On the chromatic number of powers of subdivisions of graphs

Michael Anastos, Simona Boyadzhiyska, Silas Rathke +1

For a given graph $G = (V, E)$ , we define its \emph{ $n$ th subdivision} as the graph obtained from $G$ by replacing every edge by a path of length $n$ . We also define the \emph{ $m$ th p…

math.CO2023

Ramsey goodness of $k$ -uniform paths, or the lack thereof

Simona Boyadzhiyska, Allan Lo

Given a pair of $k$ -uniform hypergraphs $(G, H)$ , the Ramsey number of $(G, H)$ , denoted by $R (G, H)$ , is the smallest integer $n$ such that in every red/blue-colouring of the edges o…

math.CO2022

On the use of senders for asymmetric tuples of cliques in Ramsey theory

Simona Boyadzhiyska, Thomas Lesgourgues

A graph $G$ is $q$ -Ramsey for a $q$ -tuple of graphs $(H_{1}, \dots, H_{q})$ if for every $q$ -coloring of the edges of $G$ there exists a monochromatic copy of $H_{i}$ in color $i$ for som…

math.CO2022

Ramsey equivalence for asymmetric pairs of graphs

Simona Boyadzhiyska, Dennis Clemens, Pranshu Gupta +1

A graph $F$ is Ramsey for a pair of graphs $(G, H)$ if any red/blue-coloring of the edges of $F$ yields a copy of $G$ with all edges colored red or a copy of $H$ with all edges colo…

math.CO2021

Ramsey simplicity of random graphs

Simona Boyadzhiyska, Dennis Clemens, Shagnik Das +1

A graph $G$ is $q$ -Ramsey for another graph $H$ if in any $q$ -edge-colouring of $G$ there is a monochromatic copy of $H$ , and the classic Ramsey problem asks for the minimum number…

math.CO2021

On the minimum degree of minimal Ramsey graphs for cliques versus cycles

Anurag Bishnoi, Simona Boyadzhiyska, Dennis Clemens +3

A graph $G$ is said to be $q$ -Ramsey for a $q$ -tuple of graphs $(H_{1}, \dots, H_{q})$ , denoted by $G \to_{q} (H_{1}, \dots, H_{q})$ , if every $q$ -edge-coloring of $G$ contains a monochromatic c…

math.CO2020

Minimal Ramsey graphs with many vertices of small degree

Simona Boyadzhiyska, Dennis Clemens, Pranshu Gupta

Given any graph $H$ , a graph $G$ is said to be $q$ -Ramsey for $H$ if every coloring of the edges of $G$ with $q$ colors yields a monochromatic subgraph isomorphic to $H$ . Further,…

Rainbow connecting 2-colorings of super-Dirac graphs

Almost-perfect colorful matchings in three-edge-colored bipartite graphs

Simultaneous edge-colourings

Odd-Ramsey numbers of complete bipartite graphs

On the chromatic number of powers of subdivisions of graphs

Ramsey goodness of k-uniform paths, or the lack thereof

On the use of senders for asymmetric tuples of cliques in Ramsey theory

Ramsey equivalence for asymmetric pairs of graphs

Ramsey simplicity of random graphs

On the minimum degree of minimal Ramsey graphs for cliques versus cycles

Minimal Ramsey graphs with many vertices of small degree

Rainbow connecting $2$ -colorings of super-Dirac graphs

Ramsey goodness of $k$ -uniform paths, or the lack thereof