3 papers
math.AP2026
On the shape of the positivity region for a free boundary problem describing cell polarization
Sebastián Flores Sepúlveda, Barbara Niethammer, Juan J. L. Velázquez
In this paper we study a mass-constrained free boundary problem modeling cell polarization, in the regime where the mass is small. In the generic case of a signal with nondegenerat…
math.AP2026
Long-time behaviour of a nonlocal model for electroporation
Barbara Niethammer, Lorena Pohl, Juan J. L. Velázquez
In this paper we analyze a model for electroporation, a biological process in which a cell membrane exposed to an external voltage becomes permeable due to the formation and growth…
math.AP2025
A note on instantaneous gelation for coagulation kernels vanishing on the diagonal
Iulia Cristian, Barbara Niethammer, Juan J. L. Velázquez
We prove that instantaneous gelation (i.e., instantaneous loss of mass) occurs for coagulation equations with sum-type kernels of homogeneity greater than one which vanish on the d…