4 papers
Curved commutators in the plane
Kangwei Li, Henri Martikainen, Tuomas Oikari
We complete the boundedness theory of commutators of Hilbert transforms along monomial curves by providing the previously missing lower bounds. This optimal result now covers…
On entangled and multi-parameter commutators
Kangwei Li, Henri Martikainen
We complement the recent theory of general singular integrals invariant under the Zygmund dilations by proving necessary and suf…
Zygmund dilations: bilinear analysis and commutator estimates
Emil Airta, Kangwei Li, Henri Martikainen
We develop both bilinear theory and commutator estimates in the context of entangled dilations, specifically Zygmund dilations $(x_1, x_2, x_3) \mapsto (δ_1 x_1, δ_2 x_2, δ_1 δ…
On the compactness of the bi-commutator
Henri Martikainen, Tuomas Oikari
We prove compactness results and characterizations for the bi-commutator of a symbol and two non-degenerate Calderón-Zygmund singular integral operators $T_1,…