Nonuniqueness of weak solutions to the SQG equation

We prove that weak solutions of the inviscid surface quasi-geostrophic (SQG) equation are not unique, thereby answering an open problem posed by De Lellis and Szekelihidi. Moreover, we also show that weak solutions of the dissipative SQG equation are not unique, even if the fractional dissipation is stronger than the square root of the Laplacian. This is joint work with T. Buckmaster and V. Vicol.Non UBCUnreviewedAuthor affiliation: UC DavisFacult