It is probably worth mentioning that Zhu recently proved the fractional version of this conjecture: that .

Xuding Zhu, The fractional version of Hedetniemi’s conjecture is true, European Journal of Combinatorics, Volume 32, Issue 7, October 2011, Pages 1168-1175, ISSN 0195-6698, 10.1016/j.ejc.2011.03.004. (http://www.sciencedirect.com/science/article/pii/S0195669811000552)

## Fractional version is true

It is probably worth mentioning that Zhu recently proved the fractional version of this conjecture: that .

Xuding Zhu, The fractional version of Hedetniemi’s conjecture is true, European Journal of Combinatorics, Volume 32, Issue 7, October 2011, Pages 1168-1175, ISSN 0195-6698, 10.1016/j.ejc.2011.03.004. (http://www.sciencedirect.com/science/article/pii/S0195669811000552)