Essential positivity conjecture for radial Toeplitz operators

From papers

Let A2A^2 be the Bergman space on the unit disk 4D44\mathbb{D}4, and let Tf:A2A2T_f:A^2\to A^2 be the Toeplitz operator with real-valued radial symbol fL(D)f\in L^\infty(\mathbb{D}). Write f~\tilde f for the Berezin transform of ff. An operator is essentially positive when its image in the Calkin algebra is positive.

Essential positivity conjecture. The operator TfT_f is essentially positive if and only if

lim infz1f~(z)0.\liminf_{|z|\to 1}\tilde f(z)\geq 0.

The preceding corollary proves this criterion when the boundary limit of f~\tilde f exists. The conjecture seeks the corresponding characterization without assuming that the limit exists; it is motivated by compactness characterizations for Toeplitz operators with measure symbols.

Progress summary

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Sources & referencesView supporting material

Primary source

A. Perälä and J. A. Virtanen, “Essential positivity”, arXiv:2212.02993 (2023).

Solutions 0

No solutions have been posted yet.