András Bátkai
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Registered User
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I work in functional analysis, my research areas are evolution equations, operator semigroups and delay differential equations.
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3h |
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Stabilization of solution to one-dimensional system of PDE You can also try to ask this at scicomp.stackexchange.com |
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Jun 15 |
answered | A book for problems in Functional Analysis |
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Jun 8 |
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Is there a strongly stable semigroup which is not uniformly bounded You are welcome :-) |
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Jun 8 |
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Replacing large-dimensional ODE systems with one PDE Self-promotion: arxiv.org/abs/1303.6235 |
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Jun 8 |
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Replacing large-dimensional ODE systems with one PDE In what sense replace? |
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Jun 8 |
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Is there a strongly stable semigroup which is not uniformly bounded The second condition means that $\|T(t)x\|$ $t>0$ is bounded for all $x$. Hence, by the uniform boundedness principle, 1. holds. |
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Jun 6 |
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trace-class embeddings A downloadable version of the cited paper is here: math.ntnu.no/conservation/2009/037.pdf |
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May 31 |
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diffusion equation Probably math.stackexchange.com would be a better place to ask this. Read the FAQ about this site and what questions are welcome here. |
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May 31 |
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diffusion equation edited tags |
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May 27 |
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Resolution of Identity This might be relevant: math.stackexchange.com/questions/298899/… |
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May 27 |
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Spectral decomposition function As you see from Robert Israels guesses, it is still unclear. Why don't you ask the professor? |
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May 26 |
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Spectral decomposition function Context would help here. Where was it? |
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May 26 |
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Numerical coincidence? It must be this question (just for reference): math.stackexchange.com/questions/396761/… |
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May 25 |
accepted | Algorithm to find exponential map of differential operators acting on function |
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May 20 |
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Proof that $L^2(0,T;X)^* = L^2(0,T;X^*)$ Sorry, I did not get this comment somehow... Yes, it seems to me as easy as you write. |
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May 20 |
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Dual space of Bochner space: is there an easier proof to show they’re isometric? See also mathoverflow.net/questions/130857/… |
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May 19 |
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Algorithm to find exponential map of differential operators acting on function The formula for the action on $f(x,y)$ is given in detail in the Engel-Nagel reference below. Does it help? |
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May 18 |
answered | Algorithm to find exponential map of differential operators acting on function |
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May 18 |
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Strong convergence in the Bochner space L^p([0,T],X) Dear Rafa, it seems that some of your formulae is incomplete, something is missing.And, in particular, I miss your question... |
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May 17 |
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$C_c^{\infty}([0,T];V)$ is dense in $C_c^{1}([0,T];V)$? A related question: mathoverflow.net/questions/130276/… |
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May 17 |
accepted | Proof that $L^2(0,T;X)^* = L^2(0,T;X^*)$ |
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May 17 |
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how to proof this Stirling related equation I am a bit slow, why is the left hand side infinite? |
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May 17 |
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Proof that $L^2(0,T;X)^* = L^2(0,T;X^*)$ added details |
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May 16 |
answered | Proof that $L^2(0,T;X)^* = L^2(0,T;X^*)$ |
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May 16 |
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Proof that $L^2(0,T;X)^* = L^2(0,T;X^*)$ I am a bit confused. If $X$ is a Hilbert space, then $L^2(0,T;X)$ is a Hilbert space (complete + norm comes from a scalar product). Hence if you also identify $X$ with its dual (as you do with $L^2$), then the statement follows. Maybe this is not what you ask? |
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May 11 |
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Variation on Fatou’s lemma for Sobolev norms Your point 2 is not the same as above: it follows immediately from the continuity of the norm. |
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May 11 |
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continuty of volume of a convex set in Rn Though I believe this question is better suited at math.stackexchange.com , let me give you a hint. How do you define your metrics on compact sets? |
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May 10 |
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Compact open topology edited tags |
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May 10 |
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$\mathcal{D}(0,T;V)$ is dense in $W(0,T)$ Volume 1: rd.springer.com/book/10.1007/978-3-642-65161-8/… , but there are three. |
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May 10 |
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$\mathcal{D}(0,T;V)$ is dense in $W(0,T)$ A standard reference on this is the monograph by Lions and Magenes: Non-Homogeneous Boundary Value Problems and Applications. Everyone refers to it for the proof... |
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May 10 |
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Integrating a weak derivative Corollary 2.2 here: math.psu.edu/bressan/PSPDF/sobolev-notes.pdf |
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May 10 |
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Integrating a weak derivative Could you lint your MSE question? I cannot find it... |
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May 9 |
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probability calculation I cannot and hence did not vote. I believe it is off-topic here because it is not research mathematics, and not because it is easy: it is not. But easy questions on advanced mathematics may be on-topic here if they come out of research. For me, it is not the difficulty that counts but the level. |
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May 8 |
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probability calculation Try math.stackexchange.com This site is for upper graduate or postgrad level questions. Also, if you ask, indicate what you already know and where your problem lies so that people can help you. |
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May 8 |
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radon-nikodým property of $\ell^\infty$ See the later answer by jbc. |
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May 8 |
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radon-nikodým property of $\ell^\infty$ It does not. You asked for a condition when a dual space has RN, and this came to my mind. |
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May 7 |
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radon-nikodým property of $\ell^\infty$ deleted 5 characters in body |
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May 7 |
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radon-nikodým property of $\ell^\infty$ deleted 173 characters in body |
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May 7 |
answered | radon-nikodým property of $\ell^\infty$ |
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May 7 |
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radon-nikodým property of $\ell^\infty$ Separable dual spaces are ok (Dunford-Pettis theorem). |
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May 7 |
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I. Kaplansky, Going up in polynomial rings, unpublished manuscript, 1972 edited tags |
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May 4 |
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null controllability of linear wave equation Is is correct that $z=y$? |
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Mar 23 |
revised |
The Periodic Schrödinger Group added 146 characters in body |
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Mar 22 |
answered | The Periodic Schrödinger Group |
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Feb 27 |
accepted | On exponential formula |
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Feb 12 |
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On exponential formula corrected link, expanded text. |
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Feb 12 |
answered | On exponential formula |
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Feb 10 |
awarded | ● Yearling |
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Feb 9 |
answered | Commutator formula in infinite dimensions |
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Jan 29 |
answered | Generator of a generated $C_0$ semigroup. |
