Self-similar solutions with fat tails for a coagulation equation with diagonal kernel

We consider self-similar solutions of Smoluchowski's coagulation equation with a diagonal kernel of homogeneity $\gamma < 1$. We show that there exists a family of second-kind self-similar solutions with power-law behavior $x^{-(1+\rho)}$ as $x \to \infty$ with $\rho \in (\gamma,1)$. To our knowledge this is the first example of a non-solvable kernel for which the existence of such a family has been established

Optimal bounds for self-similar solutions to coagulation equations with product kernel

We consider mass-conserving self-similar solutions of Smoluchowski's coagulation equation with multiplicative kernel of homogeneity $2l\lambda \in (0,1)$. We establish rigorously that such solutions exhibit a singular behavior of the form $x^{-(1+2\lambda)}$ as $x \to 0$. This property had been conjectured, but only weaker results had been available up to now