A solution theory for quasilinear singular SPDEs

Abstract: We give a construction allowing to construct local renormalised solutions to general quasilinear stochastic PDEs within the theory of regularity structures, thus greatly generalising the recent results of [BDH16,FG16,OW16]. Loosely speaking, our construction covers quasilinear variants of all classes of equations for which the general construction of [Hai14,BHZ16,CH16] applies, including in particular one-dimensional systems with KPZ-type nonlinearities driven by space-time white noise. In a less singular and more specific case, we furthermore show that the counterterms introduced by the renormalisation procedure are given by local functionals of the solution. The main feature of our construction is that it allows to exploit a number of existing results developed for the semilinear case, so that the number of additional arguments it requires is relatively small.