I am a PhD student in the research group on discrete mathematics since October 2013. During my studies of computer sciences and mathematics here in Karlsruhe, I mainly focused on graph theory and combinatorics.

I am interested in many areas of graph theory and combinatorics. Currently, I study different kinds of graph colorings and decompositions from an extremal point of view, which in particular includes graph Ramsey theory.

Latest research of mine focuses on ordered graphs, that is, graphs equipped with a linear ordering of the vertex set. I study how classical results from graph theory behave in the ordered setting.

### Research Interests

## Graph Colorings:

- chromatic number of (ordered) graphs under local constraints, conflict-free colorings, (1,r-1)-colorings

## Ramsey Theory:

- Ramsey equivalence, Ramsey multiplicity, ordered graph Ramsey theory

## Graph Decompositions:

- induced arboricity, {a,b}-factors

### Publications

- Tanja Hartmann, Jonathan Rollin, Ignaz Rutter, "
**Regular augmentation of planar graphs**" {url} Algorithmica (2014), pp. 1-65 - Maria Axenovich, Jonathan Rollin, "
**Brooks type results for conflict-free colorings and {a, b}-factors in graphs**" {file} Discrete Mathematics, 338(12):2295 – 2301, 2015 *(corrected statement of Theorem 7)* - Daniel Hoske, Jonathan Rollin, Torsten Ueckerdt, Stefan Walzer, "
**Playing weighted Tron on trees**" {url} Discrete Mathematics, 338(12):2341 – 2347, 2015 - Maria Axenovich, Jonathan Rollin, Torsten Ueckerdt, "
**Conditions on Ramsey non-equivalence**" {url} Accepted to Journal of Graph Theory - Maria Axenovich, Jonathan Rollin, Torsten Ueckerdt, "
**Chromatic number of ordered graphs with forbidden ordered subgraphs**" {url} Accepted to Combinatorica - Anton Bernshteyn, Omid Khormali, Ryan R. Martin, Jonathan Rollin, Danny Rorabaugh, Songling Shan, Andrew J. Uzzell, "
**Regular colorings and factors of regular graphs**" {url} submitted - Maria Axenovich, Daniel Goncalves, Jonathan Rollin, Torsten Ueckerdt, "
**The k-strong induced arboricity of a graph**" {url} Accepted to European Journal of Combinatorics - Maria Axenovich, Jonathan Rollin, Torsten Ueckerdt, "
**The chromatic number of ordered graphs with constrained conflict graphs**" {url} submitted

### Dissertation

- Jonathan Rollin, "Extremal and Ramsey Type Questions for Graphs and Ordered Graphs" (2017)

### Conference Talks

35'th Kolloquium über Kombinatorik, Paderborn, November, 4 - 5 2016

"Chromatic number of ordered graphs without forbidden ordered subgraphs"

6'th Polish Combinatorial Conference, Bedlewo, September 19 - 23, 2016

"Chromatic number of ordered graphs without forbidden ordered subgraphs"

Utrecht Combinatorics Workshop, Utrecht, November 7, 2014

"Brooks Type Results for Conflict-Free Colorings and {a,b}-factors in graphs"

### Workshops

Oberwolfach Seminar “Positional Games”, May 19 - 25, 2013

Rocky Mountain-Great Plains Graduate Research Workshop in Combinatorics, Ames IA, June 1 -13, 2015