# Ali Qurbani

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9
bio website location Iran- Mashhad age 26 member for 2 years, 7 months seen Jun 9 at 19:34 profile views 206

# 29 Questions

 4 ‎‎$‎T:\ell^{‎2‎} \rightarrow ‎\ell^{‎2‎}‎$ ‎‎defined ‎by ‎‎$‎T(\{x_{n}\})=\{2^{-n}x_{n}\}$ ‎is ‎compact 3 Is ‎‎$‎\mu‎$‎ ‎complete ‎measure?‎ 2 ‎‎If $A$ contains ‎an ‎idempotent $e‎$ (‎‎$‎e‎\neq ‎‎0,1‎‎$‎) , then $‎\Omega(A)‎$ ‎is ‎disconnected 1 ‎If ‎‎$‎X$ is an infinite-dimensional Banach space and ‎‎$‎‎u‎\in ‎B(X)‎$ ,then $\bigcap_{v\in K(X)}\sigma(u+v) =\cdots$ 1 Finding ‎the level ‎curves ‎of $z= f(x,y)$

# 131 Reputation

 +5 $\widehat{a}: \Omega(A)‎\rightarrow‎ \mathbb{C}~,~\tau‎ \mapsto \tau(A)‎‎$ -2 $\mu$ is semifinite iff $f(x)<\infty$ ,$\forall x \in X$ and … -2 If $f$ is non-negative and summable, then $\mu (\{x∈X: f(x) > c\}) < \frac{1}{c} \int f \,d\mu$. +10 Example of a normal operator which has no eigenvalues

 3 evaluation of the limit given by $\lim_{n\to \infty} \sin( (2n\pi + \frac{1}{2n\pi}) \sin(2n\pi + \frac{1}{2n\pi}))$ 2 Example of a normal operator which has no eigenvalues 0 Evaluate $\lim_{n\to\infty}\sum_{r=1}^{n}\sin\frac{r\pi}{n}$

# 23 Tags

 3 real-analysis × 10 0 measure-theory × 4 2 operator-theory × 17 0 compact-operators × 4 2 eigenvalues-eigenvectors × 2 0 abstract-algebra × 2 0 banach-algebras × 10 0 multivariable-calculus × 2 0 functional-analysis × 6 0 operator-algebras × 2

# 1 Account

 Mathematics 131 rep 9