Two singular limits in models of tissue growth: incompressible limit and stochastic homogenization

Olga Turanova
Michigan State University

In the past decade there have been many results on the relationship between models of tissue growth based on the porous medium equation and those based on the Hele-Shaw problem. In particular, the latter arises in the limit of large diffusion exponent of the former. This is called the incompressible limit. I will begin by presenting a recent result along these lines; the novelty is that the limiting problem exhibits heterogeneity on the free boundary. This motivates the topic of the next part of the talk: stochastic homogenization of a Hele-Shaw problem with oscillation on both the interior and the free boundary. The result that I will describe holds only in one spatial dimension; however, it is new even in the setting of periodic coefficients. Based on joint works with Anthony Sulak and with Paul Yuming Zhang.