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bio website maths.lancs.ac.uk/~kania
location Lancaster, UK
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2d
comment Questions of Hyperspace of Compact Sets
I guess that the question is about convergence in the Vietoris topology.
Jan
24
comment Is there a proof that $L^p([0,1],X)$ has the Radon Nikodym Property that uses the characterization via Lipschitz continuous functions?
Please look at Theorem 1.1 here: annals.math.princeton.edu/wp-content/uploads/…
Jan
20
comment Spectral Measures: Equivalence
(+1) indeed -- I upvoted this nice answer.
Jan
20
revised Semi-direct decompositions of Banach algebras
a better title
Jan
20
answered Semi-direct decompositions of Banach algebras
Jan
14
revised Polar decomposition
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Jan
14
comment Integration of $\int_{-\infty}^{\infty}\frac{\cos x}{a^2+x^2}dx$
Use residues. en.wikipedia.org/wiki/…
Jan
11
revised Group isomorphism for deck transformation in covering space.
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Jan
8
revised For a hermitian element $a$ in a $C^*$-algebra, show that $\|a^{2n}\| = \|a\|^{2n}$
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Jan
8
comment For a hermitian element $a$ in a $C^*$-algebra, show that $\|a^{2n}\| = \|a\|^{2n}$
Ah, I misread your post. Sorry about that.
Jan
7
revised Does separability imply the Lindelöf property?
minor changes
Jan
7
comment For a hermitian element $a$ in a $C^*$-algebra, show that $\|a^{2n}\| = \|a\|^{2n}$
Well, it is some element. What is the spectrum of the identity? Take any element with spectrum which is not $\{1\}$, it cannot play the role of the identity. By the way, the string of equalities you wrote would imply that $\|a\|^n=1$. I suggest deleting this answer.
Jan
7
comment For a hermitian element $a$ in a $C^*$-algebra, show that $\|a^{2n}\| = \|a\|^{2n}$
$a$ need not correspond to the identity.
Dec
30
comment Continuity of a positive preserving operator between C(X) and C(Y)
The proof does carry over. math.stackexchange.com/questions/426487/…
Dec
28
accepted An elliptic integral of first kind expresses the time of motion along an elliptic phase curve in the corresponding Hamiltonian system
Dec
26
revised Are there spaces “smaller” than $c_0$ whose dual is $\ell^1$?
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Dec
26
revised An elliptic integral of first kind expresses the time of motion along an elliptic phase curve in the corresponding Hamiltonian system
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Dec
26
revised $p^2=p$ in closure of ideal $I$ of Banach algebra implies $p\in I$.
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Dec
25
revised An elliptic integral of first kind expresses the time of motion along an elliptic phase curve in the corresponding Hamiltonian system
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Dec
25
revised $p^2=p$ in closure of ideal $I$ of Banach algebra implies $p\in I$.
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