TY - JOUR
T1 - On a Class of Calderón-Zygmund Operators Arising from Projections of Martingale Transforms
AU - Perlmutter, Michael
N1 - Publisher Copyright:
© 2014, Springer Science+Business Media Dordrecht.
PY - 2014/2
Y1 - 2014/2
N2 - We prove that a large class of operators, which arise as the projections of martingale transforms of stochastic integrals with respect to Brownian motion, as well as other closely related operators, are in fact Calderón-Zygmund operators. These operators have played an important role in studying the Lp boundedness, 1 < p < ∞, of classical Calderón-Zygmund operators such as the Beurling-Ahlfors transform and the Riesz transform. Showing that these operators are Calderón-Zygmund implies that they are not only bounded on Lp, but also satisfy weak-type inequalities. Unlike the boundedness on Lp, which can be obtained directly from the Burkholder martingale transform inequalities, the weak-type estimates do not follow from the corresponding martingale results. The reason for this is that the Lp boundedness of these operators uses conditional expectation, which unfortunately does not preserve weak-type inequalities. Instead, we represent these operators in a purely analytic fashion as integration against a kernel and obtain our result by showing that our kernel satisfies suitable estimates.
AB - We prove that a large class of operators, which arise as the projections of martingale transforms of stochastic integrals with respect to Brownian motion, as well as other closely related operators, are in fact Calderón-Zygmund operators. These operators have played an important role in studying the Lp boundedness, 1 < p < ∞, of classical Calderón-Zygmund operators such as the Beurling-Ahlfors transform and the Riesz transform. Showing that these operators are Calderón-Zygmund implies that they are not only bounded on Lp, but also satisfy weak-type inequalities. Unlike the boundedness on Lp, which can be obtained directly from the Burkholder martingale transform inequalities, the weak-type estimates do not follow from the corresponding martingale results. The reason for this is that the Lp boundedness of these operators uses conditional expectation, which unfortunately does not preserve weak-type inequalities. Instead, we represent these operators in a purely analytic fashion as integration against a kernel and obtain our result by showing that our kernel satisfies suitable estimates.
KW - Calderón-Zygmund operators
KW - Martingale transforms
KW - Stable processes
UR - http://www.scopus.com/inward/record.url?scp=84925504127&partnerID=8YFLogxK
UR - https://doi.org/10.1007/s11118-014-9438-1
U2 - 10.1007/s11118-014-9438-1
DO - 10.1007/s11118-014-9438-1
M3 - Article
AN - SCOPUS:84925504127
SN - 0926-2601
VL - 42
SP - 383
EP - 401
JO - Potential Analysis
JF - Potential Analysis
IS - 2
ER -