Convergence of Series of Translations.
Coorbit space theory for quasi-Banach spaces
We generalize the classical coorbit space theory developed by Feichtinger and Gröchenig to quasi-Banach spaces. As a main result we provide atomic decompositions for coorbit spaces defined with respect to quasi-Banach spaces. These atomic decompositions are used to prove fast convergence rates of best n-term approximation schemes. We apply the abstract theory to time-frequency analysis of modulation spaces , 0 < p,q ≤ ∞.
Corrigendum to 'A Note on Wavelets and S-asymptotics'
Corrigendum to the paper "Pointwise convergence for expansions in surface harmonics of arbitrary dimension".
Costruzione di un sistema di polinomi ortonormali a partire da due suoi polinomi consecutivi
The following result is proved: to give two consecutive polynomials , of an orthonormal system is equivalent to assign the first moments of the Lebesgue-Stieltjes measure associated with the system.
Counting peaks and valleys in a partition of a set.
Critical length for a Beurling type theorem
In a recent paper [3] C. Baiocchi, V. Komornik and P. Loreti obtained a generalisation of Parseval's identity by means of divided differences. We give here a proof of the optimality of that theorem.
Curriculum vita of Prof. Vasil Atanasov Popov
Our primary goal in this preamble is to highlight the best of Vasil Popov’s mathematical achievements and ideas. V. Popov showed his extraordinary talent for mathematics in his early papers in the (typically Bulgarian) area of approximation in the Hausdorff metric. His results in this area are very well presented in the monograph of his advisor Bl. Sendov, “Hausdorff Approximation”.
Cyclic subspaces for unitary representations of LCA groups; generalized Zak transform
We just published a paper showing that the properties of the shift invariant spaces, ⟨f⟩, generated by the translates by ℤⁿ of an f in L²(ℝⁿ) correspond to the properties of the spaces L²(𝕋ⁿ,p), where the weight p equals [f̂,f̂]. This correspondence helps us produce many new properties of the spaces ⟨f⟩. In this paper we extend this method to the case where the role of ℤⁿ is taken over by locally compact abelian groups G, L²(ℝⁿ) is replaced by a separable Hilbert space on which a unitary representation...