2 papers
math.AP2026
Quasiconvexity of the Burkholder function on symmetric matrices
André Guerra
We use Morse Theory to prove that the Burkholder function is quasiconvex on symmetric matrices, which implies several sharp inequalities for the Beurling--Ahlfors transform when ac…
math.AP2025
Lower semicontinuity, Stoilow factorization and principal maps
Kari Astala, Daniel Faraco, André Guerra +2
We consider a strengthening of the usual quasiconvexity condition of Morrey in two dimensions, which allows us to prove lower semicontinuity for functionals which are unbounded as…