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Apr
1
comment Square root of a complex matrix commuting with a given one
Yes, but just a remark here: this holomorphic method provides an explicit formula that can be numerically calculated and approximated. The algebraic proofs above require the knowledge of unknown quantities, such as the minimal polynomial, or the Jordan form. Although perfect theoretically, an algebraic method for this problem will require a very large time to provide a simple approximation of a commuting square-root: the numerical cost of the determination of the minimal polynomial or of the Jordan form is huge, compared to the simple algorithm to approximate a simple integral.
Apr
1
answered Square root of a complex matrix commuting with a given one
Mar
18
asked Embeddings of Sobolev spaces
Mar
17
asked Inequality for Laguerre polynomials
Mar
13
answered Multivariate Hermite Polynomials
Mar
5
answered Smooth but non-analytic kernel functions
Mar
5
answered Lower bounds for norms of commutators
Mar
5
awarded  Yearling
Mar
1
answered Weak convergence in the space of Lipschitz Functions
Feb
25
answered Relationship of eigenvalue/eigenvector of hermitian matrix R and QRQ (Q is diagonal)
Feb
21
comment Reflexive Besov spaces Bs,p,q
No: true only if $1\le p,q<+\infty.$
Feb
20
answered General systems of linear differential equations with variable coefficients
Feb
11
answered When one can expect $\widehat{(fg)} = \hat{f} \ast \hat{g}$; $f, g\in L^{1} (G)$?
Feb
11
answered wavefront is a coisotropic
Feb
9
answered Real-analytic variant of theorem 4.2.5 of Duistermaat's “FIO”, 1996
Feb
3
answered Estimate the analytical wavefront set $WF_A(u)$ given $WF_A(A_K u)$
Jan
30
answered Practical way to check whether a distribution is conormal
Jan
30
comment A question which belongs to a class of Zygmund functions
The book Fourier Analysis and Nonlinear Partial Differential Equations, Grundlehren Vol. 343 by Bahouri, Hajer, Chemin, Jean-Yves, Danchin, Raphaël contains plenty of information on basic Fourier analysis.
Jan
29
answered A question which belongs to a class of Zygmund functions
Jan
28
asked Positive kernel property