In this paper, we will provide a simple method for starting with a given finite frame for an $n$-dimensional Hilbert space $mathcal{H}_n$ with nonzero elements and producing a frame which is $epsilon$-nearly Parseval and $epsilon$-nearly unit norm. Also, the concept of the $epsilon$-nearly equal frame operators for two given frames is presented. Moreover, we characterize all bounded invertible ...

In this paper, we present a super-convergence result for the Local Discontinuous Galerkin method for a model elliptic problem on Cartesian grids. We identify a special numerical ux for which the L 2-norm of the gradient and the L 2-norm of the potential are of order k + 1=2 and k + 1, respectively, when tensor product polynomials of degree at most k are used; for arbitrary meshes, this special ...

We find an expression for the Gateaux derivative of C⁎-algebra norm. Using this, we obtain a characterization orthogonality operator A∈B(H,K) to subspace, under assumption dist(A,K(H,K))<‖A‖. subdifferential set norm function at A∈B(H) when dist(A,K(H))<‖A‖. also give new proofs known results on closely related notions smooth points and Birkhoff-James spaces B(H) Cb(Ω), respectively.

Abstract In this paper we characterize when non-classical polynomials are necessary in the inverse theorem for Gowers $U^k$ -norm. We give a brief deduction of fact that bounded function on $\mathbb F_p^n$ with large -norm must correlate classical polynomial $k\le p+1$ . To best our knowledge, result is new $k=p+1$ (when $p&gt;2$ ). then prove over all $k\ge p+2$ , completely characterising suf...

We prove two results about smoothness in Banach spaces of the type C(K). Both build upon earlier papers of the first named author [3,4]. We first establish a special case of a conjecture that remains open for general Banach spaces and concerns smooth approximation. We recall that a bump function on a Banach space X is a function β : X → R which is not identically zero, but which vanishes outsid...

We prove two results about smoothness in Banach spaces of the type C(K). Both build upon earlier papers of the first named author [3,4]. We first establish a special case of a conjecture that remains open for general Banach spaces and concerns smooth approximation. We recall that a bump function on a Banach space X is a function β : X → R which is not identically zero, but which vanishes outsid...

If K is a 0-symmetric, bounded, convex body in the Euclidean n-space R (with a fixed origin O) then it defines a norm whose unit ball is K itself (see [12]). Such a space is called Minkowski normed space. The main results in this topic collected in the survey [16] and [17]. In fact, the norm is a continuous function which is considered (in the geometric terminology as in [12]) as a gauge functi...

The affine synthesis operator Sc = P j>0 P k∈Zd cj,kψj,k is shown to map the mixed-norm sequence space `(`) surjectively onto L(R) under mild conditions on the synthesizer ψ ∈ L(R), 1 ≤ p < ∞, with R Rd ψ dx = 1. Here ψj,k(x) = |det aj |ψ(ajx−k), and the dilation matrices aj expand, for example aj = 2I . Affine synthesis further maps a discrete mixed Hardy space `(h) onto H(R). Therefore the H-...

Let X be a normed linear space over K (R or C). A function P : X → K is said to be a 2-polynomial if there is a bilinear functional Π : X × X → K such that P (x) = Π(x, x) for every x ∈ X. The norm of P is defined by P = sup{|P (x)| : x = 1}. It is known that if X is an inner product space, then every 2-polynomial defined in a linear subspace of X can be extended to X preserving the norm. On th...

In this paper, we present the first a priori error analysis for the local discontinuous Galerkin (LDG) method for a model elliptic problem. For arbitrary meshes with hanging nodes and elements of various shapes, we show that, for stabilization parameters of order one, the L2-norm of the gradient and the L2-norm of the potential are of order k and k + 1/2, respectively, when polynomials of total...