This review is dedicated to recent results on the 2d parabolic-elliptic Patlak-Keller-Segel model, and on its variant in higher dimensions where the diffusion is of critical porous medium type. Both of these models have a critical mass $M_c$ such that the solutions exist globally in time if the mass is less than $M_c$ and above which there are solutions which blowup in finite time. The main tools, in particular the free energy, and the idea of the methods are set out. A number of open questions are also stated.
@article{hal-00620500,
author = {Blanchet, Adrien},
title = {On the parabolic-elliptic Patlak-Keller-Segel system in dimension 2 and higher},
journal = {HAL},
volume = {2011},
number = {0},
year = {2011},
language = {en},
url = {http://dml.mathdoc.fr/item/hal-00620500}
}
Blanchet, Adrien. On the parabolic-elliptic Patlak-Keller-Segel system in dimension 2 and higher. HAL, Tome 2011 (2011) no. 0, . http://gdmltest.u-ga.fr/item/hal-00620500/