The following notes are from the Ramsey DocCourse in Prague 2016. The notes are taken by me and I have edited them. In the process I may have introduced some errors; email me or comment below and I will happily fix them.

**Title**: Fractional Hedetniemi’s conjecture and Chromatic Ramsey number

**Lecturer**: Xuding Zhu

**Date**: November 9, 2016

**Main Topics**: Chromatic Ramsey numbers, lower bound for them, Hedetniemi’s conjecture, fractional Hedetniemi’s conjecture.

**Definitions:** -Ramsey number, -Ramsey number, wreath product, product graph, graph homomorphism, fractional chromatic number