Tuomas Oikari

activity

20242026

collaborators

8 papers

math.CA2026

Bounds for the maximal and Riesz potential operators with variable fractionality

Francisco GonÃ§alves, Tuomas Oikari

We prove $L^{p (\cdot)}$ -to- $L^{q (\cdot)}$ bounds for variable versions of the fractional maximal $M^{I^\pm (\cdot)}$ and Riesz potential $I^{I^\pm (\cdot)}$ operators. The changing fractio…

math.CA2026

Curved commutators in the plane

Kangwei Li, Henri Martikainen, Tuomas Oikari

We complete the $L^{p}$ boundedness theory of commutators of Hilbert transforms along monomial curves by providing the previously missing lower bounds. This optimal result now covers…

math.FA2025

Factorizations for variable exponent Muckenhoupt weights

Stefanos Lappas, Tuomas Oikari

Given two variable exponent Muckenhoupt weights $w \in A_{p (\cdot)}$ and $w_{1} \in A_{p_{1} (\cdot)}$ , we prove that for all small enough $I^¸ > 0,$ there holds that $w_0\in A_{p_0(\cdot)},…

math.FA2025

Approximation in HÃ¶lder Spaces

Carlos Mudarra, Tuomas Oikari

We introduce new vanishing subspaces of the homogeneous HÃ¶lder space $C ˙^{0, I ¨ } (X, Y)$ in the generality of a doubling modulus $I ¨ $ and normed spaces $X$ and $Y .$ For many cou…

math.CA2025

Domains with globally exponentially integrable parabolic forward-in-time BMO

Kim MyyrylÃ¤inen, Tuomas Oikari, Olli Saari

We characterize those open sets of the space time in which parabolic forward-in-time BMO functions are in a certain forward-in-time exponential integrability class. The characteriz…

math.CA2025

Note on the compactness of commutators

Tuomas Oikari

The optimal sufficient conditions for the $L^{p}$ -to- $L^{q}$ compactness of commutators of singular integral operators of both CalderÃ³n-Zygmund and of rough type are shown in the diff…