No Arabic abstract
We continue the study of low regularity behavior of the viscous nonlinear wave equation (vNLW) on $mathbb R^2$, initiated by v{C}anic and the first author (2021). In this paper, we focus on the defocusing quintic nonlinearity and, by combining a parabolic smoothing with a probabilistic energy estimate, we prove almost sure global well-posedness of vNLW for initial data in $mathcal H^s (mathbb R^2)$, $s >- frac 15$, under a suitable randomization.
We prove global well-posedness for 3D Dirac equation with a concentrated nonlinearity.
We prove global well-posedness for the 3D Klein-Gordon equation with a concentrated nonlinearity.
In this paper we prove local well-posedness in Orlicz spaces for the biharmonic heat equation $partial_{t} u+ Delta^2 u=f(u),;t>0,;xinR^N,$ with $f(u)sim mbox{e}^{u^2}$ for large $u.$ Under smallness condition on the initial data and for exponential nonlinearity $f$ such that $f(u)sim u^m$ as $uto 0,$ $m$ integer and $N(m-1)/4geq 2$, we show that the solution is global. Moreover, we obtain a decay estimates for large time for the nonlinear biharmonic heat equation as well as for the nonlinear heat equation. Our results extend to the nonlinear polyharmonic heat equation.
We prove global well-posedness for the $3D$ radial defocusing cubic wave equation with data in $H^{s} times H^{s-1}$, $1>s>{7/10}$.
We establish probabilistic small data global well-posedness of the energy-critical Maxwell-Klein-Gordon equation relative to the Coulomb gauge for scaling super-critical random initial data. The proof relies on an induction on frequency procedure and a modified linear-nonlinear decomposition furnished by a delicate probabilistic parametrix construction. This is the first global existence result for a geometric wave equation for random initial data at scaling super-critical regularity.