Essential positivity conjecture for radial Toeplitz operators

About 4 years old · traced to

Let A2A^2 be the Bergman space on the unit disk 4D44\mathbb{D}4, and let Tf:A2→A2T_f:A^2\to A^2 be the Toeplitz operator with real-valued radial symbol f∈L∞(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 inf⁡∣z∣→1f~(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.

References

Primary source

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

Progress summary

Never refreshed

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

Solutions 0

No solutions have been posted yet.