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Speaker: Professor Galia Dafni (Concordia University)
(1) Topic:
A
John-Nirenberg type inequality for Q spaces
Time : Jan. 5 (Fri.) , 2007
AM 10:30
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Abstract:
Q spaces in several variables were introduced by Essen, Janson, Peng and
Xiao. Depending on a real parameter alpha, they form a scale of subspaces
of BMO, the space of functions of bounded mean oscillation. They satisfy
many properties analogous to those of BMO, such as the relation with
Carleson measures, duality and decomposition.
One of the main characterizations of BMO functions is via the
John-Nirenberg inequality, and in joint work with Hong Yue, we prove an
analogue of this inequality for Q spaces. Our results are a modification
of a conjecture of Essen, Janson, Peng and Xiao, and we show, by a
counterexample, the necessity for this modification.
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(2) Topic:
Div-curl
lemmas, local Hardy spaces and BMO
Time : Jan. 5 (Fri.) , 2007
PM 1:30
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Abstract:
I will present some nonhomogeneous versions of the div-curl lemma of
Coifman, Lions, Meyer and Semmes in the context of local Hardy spaces
(in the sense of Goldberg), on ${\bf R}^n$ and on domains. I will also
discuss a version for BMO on domains (joint work with Chang and
Sadosky).
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