Mean value theorems and a Taylor theorem for vector valued functions

Wiener Tauberian Theorems for Vector - Valued Functions

Different versions of Wiener’s Tauberian theorem are discussed for the generalized group algebra LI(G,A) (of integrable functions on a locally compact abelian group G taking values in a commutative semisimple regular Banach algebra A) using A-valued Fourier transforms. A weak form of Wiener’s Tauberian property is introduced and it is proved that LI(G,A) is weakly Tauberian if and only if A is....

Harmonic functions via restricted mean-value theorems

Let f be a function on a bounded domain Ω ⊆ R and δ be a positive function on Ω such that B(x, δ(x)) ⊆ Ω. Let σ(f)(x) be the average of f over the ball B(x, δ(x)). The restricted mean-value theorems discuss the conditions on f, δ, and Ω under which σ(f) = f implies that f is harmonic. In this paper, we study the stability of harmonic functions with respect to the map σ. One expects that, in gen...

Liftings and Mean Value Theorems for Automorphic L-functions

Chevalley Restriction Theorem for Vector-valued Functions on Quantum Groups

We generalize Chevalley’s theorem about restriction Res : C[g]g → C[h]W to the case when a semisimple Lie algebra g is replaced by a quantum group and the target space C of the polynomial maps is replaced by a finite dimensional representation V of this quantum group. We prove that the restriction map Res : (Oq(G) ⊗ V )Uq(g) → O(H) ⊗ V is injective and describe the image.

Mean-value Theorems for Multiplicative Arithmetic Functions of Several Variables

Let f : Nn → C be an arithmetic function of n variables, where n ≥ 2. We study the mean-value M(f) of f that is defined to be lim x1,...,xn→∞ 1 x1 · · ·xn ∑ m1≤x1, ... , mn≤xn f(m1, . . . , mn), if this limit exists. We first generalize the Wintner theorem and then consider the multiplicative case by expressing the mean-value as an infinite product over all prime numbers. In addition, we study ...