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1d
accepted power series expansion of the square root of a Hermitian matrix
2d
comment power series expansion of the square root of a Hermitian matrix
How is the condition $2I-c^{-1}H\ge 0$ analogous to the condition $x=0$ for $x=I-c^{-1}H$?
2d
comment power series expansion of the square root of a Hermitian matrix
You are rather using the expansion of $\sqrt x=\sqrt{1-(1-x)}$ near $x=0$ which is very slowly converging, aren't you?
Aug
26
awarded  Popular Question
Feb
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awarded  Popular Question
Jul
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awarded  Curious
Jan
3
comment Looking for the functions $\alpha_n(x)$ that satisfy $\sum_{n=0}^{\infty} e^{i \alpha_n(x)}\frac{H_n(x)}{\sqrt{2^n n!}}=0$
@Mr.G The question focuses on real $\alpha_n(x)$, but I would be interested if you can find complex ones!
Dec
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awarded  Promoter
Dec
27
revised Looking for the functions $\alpha_n(x)$ that satisfy $\sum_{n=0}^{\infty} e^{i \alpha_n(x)}\frac{H_n(x)}{\sqrt{2^n n!}}=0$
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Dec
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comment Looking for the functions $\alpha_n(x)$ that satisfy $\sum_{n=0}^{\infty} e^{i \alpha_n(x)}\frac{H_n(x)}{\sqrt{2^n n!}}=0$
@IgorRivin Any of them.
Dec
26
asked Looking for the functions $\alpha_n(x)$ that satisfy $\sum_{n=0}^{\infty} e^{i \alpha_n(x)}\frac{H_n(x)}{\sqrt{2^n n!}}=0$
Nov
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comment Constrained variational calculus: Are we allowed to make use of the constraint before taking variations?
@OccupyGezi Will there be any need for using Lagrange multiplier after imposing the constraint?
Nov
3
asked Functions generating prime numbers in math packages
Oct
27
awarded  Popular Question
Sep
21
answered Geometric meaning of block-diagonalization of a matrix
Apr
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revised Constrained variational calculus: Are we allowed to make use of the constraint before taking variations?
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Apr
14
asked Constrained variational calculus: Are we allowed to make use of the constraint before taking variations?
Apr
9
comment differential equation of the square root of a matrix
I am wondering why the trajectory lies in the commutant of the algebra generated by A and B. Consider $M(dt)$ where $dt$ is an infinitismal time step. $M(dt)=M(0)+A.M(0).B.dt$ why does this commute with $A$ and $B$ if $M(0)$ does ?
Apr
7
asked differential equation of the square root of a matrix
Mar
20
awarded  Yearling