Uwe Franz
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Registered User
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beginner here
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Apr 26 |
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Existence of a projection operator onto a classical set of density matrices What do you want to take as the domain of your projection? Are you looking for something that sends general states to classical states (i.e. the domain is not a linear space, but also a convex subset of a linear space)? |
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Mar 30 |
revised |
stopping time expectation for gambler’s ruin added 331 characters in body; added 1 characters in body |
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Mar 30 |
answered | stopping time expectation for gambler’s ruin |
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Mar 18 |
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Open problems in the theory of compact quantum groups Finally on ArXiv --- here is a link to the preprint arxiv.org/abs/1303.2151. |
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Mar 6 |
asked | What are the sub $C^*$-algebras of $C(X,M_n)$? |
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Feb 26 |
accepted | Real forms of Drinfeld-Jimbo quantum groups |
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Feb 26 |
awarded | ● Enthusiast |
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Feb 26 |
revised |
Real forms of Drinfeld-Jimbo quantum groups added 1 characters in body |
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Feb 26 |
answered | Real forms of Drinfeld-Jimbo quantum groups |
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Feb 21 |
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What is quantum Brownian motion? Thanks! There are also the quantum walks (see, e.g., en.wikipedia.org/wiki/Quantum_walk, arxiv.org/abs/quant-ph/0206053, arxiv.org/abs/quant-ph/0303081), which are interesting "analogs" to random walks. But they are quite different from the quantum Wiener process. |
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Feb 21 |
answered | What is quantum Brownian motion? |
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Feb 20 |
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When is a $*$-homomorphism between multiplier algebras strictly continuous? Unital in which sense? For $\phi(1)=1$, $A$ has to be unital and then you have $M(A)=A$. |
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Feb 19 |
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Open problems in the theory of compact quantum groups Thanks! The party still goes on, as far as I am concerned. |
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Feb 17 |
accepted | When is a $*$-homomorphism between multiplier algebras strictly continuous? |
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Feb 15 |
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Finding invariant Borel Probability Measures for a contraction map See math.stackexchange.com/questions/304865/… |
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Feb 15 |
answered | When is a $*$-homomorphism between multiplier algebras strictly continuous? |
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Feb 14 |
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Optimal fitting of spheres in a cylinder. Also posted on stackexchange, see math.stackexchange.com/questions/303872/…. |
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Feb 12 |
awarded | ● Nice Answer |
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Feb 12 |
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Mathematicians whose works were criticized by contemporaries but became widely accepted later Louis Bachelier (see en.wikipedia.org/wiki/Bachelier, fr.wikipedia.org/wiki/Louis_Bachelier) |
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Feb 12 |
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Mathematicians whose works were criticized by contemporaries but became widely accepted later Wolfgang Döblin (see fr.wikipedia.org/wiki/Wolfgang_D%C3%B6blin, en.wikipedia.org/wiki/Wolfgang_Doeblin) |
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Feb 12 |
answered | Mathematicians whose works were criticized by contemporaries but became widely accepted later |
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Feb 12 |
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Math major at 36 All the threads which quid indicated have been closed... how long will this one survive? |
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Feb 12 |
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Two different analytic curves cannot intersect in infinitely many points Do you want the intersection points to have an accumulation point? |
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Feb 11 |
answered | Locally Compact Quantum Groups application |
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Feb 11 |
revised |
Reference request for Plancherel measure added 115 characters in body |
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Feb 11 |
answered | Reference request for Plancherel measure |
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Feb 10 |
awarded | ● Disciplined |
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Feb 7 |
accepted | Can one view the Independent Product in Probability categorially? |
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Feb 6 |
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Can one view the Independent Product in Probability categorially? No problem, take your time. I posted a somewhat related question yesterday on stackexchange, namely about examples of universal constructions in probability theory, see math.stackexchange.com/questions/295254/…. |
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Feb 6 |
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Can one view the Independent Product in Probability categorially? edited body |
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Feb 6 |
answered | Can one view the Independent Product in Probability categorially? |
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Feb 5 |
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why we are finding the stability for functional equations? Can you give us some examples what you mean by "stability"? |
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Feb 3 |
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system of homogeneous matrix equations For $n=2$ the condition that the mixed term vanishes just means that $AB=−BA$, so those are the only solutions. In general I don't know. Does $ABB+BAB+BBA=0=AAB+ABA+BAA$ imply $AB=qBA$ with q a primitive 3rd root of unity? What do the solutions your found for $n=3$ say? |
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Feb 2 |
awarded | ● Civic Duty |
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Feb 1 |
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fourier analytic proofs see mathoverflow.net/faq#communitywiki |
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Feb 1 |
answered | system of homogeneous matrix equations |
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Feb 1 |
revised |
Good examples of random variables whose image is not a measurable set? deleted 2 characters in body |
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Jan 30 |
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Good examples of random variables whose image is not a measurable set? I think that is the right setting for the question. |
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Jan 30 |
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Good examples of random variables whose image is not a measurable set? added 1 characters in body |
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Jan 30 |
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Good examples of random variables whose image is not a measurable set? Yes, in probability one takes usually the Borel σ-algebra on the range (when this is a topological space, in standard courses it is R or Rd anyway) and an arbitrary (complete) σ-algebra on the domain (see, e.g., mathoverflow.net/questions/31603/…). Therefore it is natural that the map f:R→R in Dynkin's lemma should be Borel, too |
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Jan 29 |
asked | Good examples of random variables whose image is not a measurable set? |
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Jan 28 |
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Probability density that minimizes the sample range @Eckhard: That's not a concave function on all of [0,1]. |
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Jan 26 |
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Quantization of a classical system (e.g. the case of a billard) @Alexander: Yes, maybe I should edit my answer. The theorems I had in mind actually require the quantisation map from class. to quantum observables to be a Lie algebra homomorphism (not just to first order in $\hbar$), see, e.g., Theorem 5.4.9 in Abraham-Marsden. Then there are two ways out: (1) restrict to sub Lie algebras, e.g. observables that are affine functions in the momenta. This leads, e.g., to the Borel quantisation discussed in the second paper (I learned QM from the first author of that paper, sorry) (2) relax to first order equality, this leads to deformation quantisation. |
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Jan 26 |
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Quantization of a classical system (e.g. the case of a billard) @Alexander: Yes, I should have said, there is no unique generally accepted method. I think the non-uniqueness is the price you have to pay to work around the no-go theorems. Maybe "physical intuition" can work to find the "right" quantisation (if you are a physicist). |
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Jan 26 |
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Quantization of a classical system (e.g. the case of a billard) You can weaken the conditions, that leads to deformation quantisation, Borel quantisation, etc. But I think there is no generally accepted method that works in all situations. |
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Jan 25 |
answered | Quantization of a classical system (e.g. the case of a billard) |
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Jan 25 |
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“geometric” description of the algebra of central functions on a Lie group Many thanks, Jim! My question was mainly for good references, to find out how well this spaces are understood. |
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Jan 25 |
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“geometric” description of the algebra of central functions on a Lie group Thank you very much, Allen and Robert, your explanations are very helpful for me! |
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Jan 23 |
revised |
“geometric” description of the algebra of central functions on a Lie group added 718 characters in body |
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Jan 23 |
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“geometric” description of the algebra of central functions on a Lie group processes has only one parameter. Of course we already know that this is true more generally for simple compact Lie groups, it has to be a multiple of the Laplace-Beltrami operator. |
