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# Fermion

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## Registered User

 Name Fermion Member for 1 year Seen Jun 15 at 18:42 Website Location Age
I am a math PhD student in the US.
 Jun14 comment Is Bir$(X)$ trivial if there does not exists $Y$ birational to $X$?@Angelo, Yves You are totally right. In fact the question is not of the form I actually want to solve. Please let me think for a bit to modify my question accordingly. Jun14 comment Is Bir$(X)$ trivial if there does not exists $Y$ birational to $X$?You are right. Of course I mean birational to $X$ but not isomorphic $X$. I corrected. Thank you for pointing out mistake. Jun14 revised Is Bir$(X)$ trivial if there does not exists $Y$ birational to $X$?added 27 characters in body Jun14 asked Is Bir$(X)$ trivial if there does not exists $Y$ birational to $X$? Jun3 revised A question on existence of degeneration of Enriques surface. deleted 23 characters in body Jun2 awarded ● Critic Jun1 asked A question on existence of degeneration of Enriques surface. Jun1 comment The central fiber of this family of surfaces? It should be $tB-C^2$. Thank you for pointing out the typo. Jun1 revised The central fiber of this family of surfaces? typo corrected Jun1 asked The central fiber of this family of surfaces? Apr22 comment Is $\pi_1(\widetilde{X/G})$ always finite if $\pi_1(X)$ is finite?Thank you for the nice answer, Francesco. I was a bit surprised to know that my question was not as easy as I had initially expected. Apr21 asked Is $\pi_1(\widetilde{X/G})$ always finite if $\pi_1(X)$ is finite? Mar21 comment Stability of $T_{\mathbb{P}^2}$ and $\Omega_{\mathbb{P}^2}$?Thank you for the answer, but could you explain a bit more? I don't know why it is enough to check $H^0(T_{\mathbb{P}^2}(-2))=0$. I am not familiar with this field. Mar21 asked Stability of $T_{\mathbb{P}^2}$ and $\Omega_{\mathbb{P}^2}$? Feb27 comment Geometric treatment of the Ward-Takahashi identityCould you explain what you mean by Ward-Takahashi identity in your question, please? Feb22 awarded ● Yearling Feb11 comment Lifting a birational map of $X/G$ to a birational map of $X$?Doesn't your example have fixed locus $f=0$? Jan19 comment Are rational sections of a vector bundle useful?Thank ou for the answer. Jan17 asked Are rational sections of a vector bundle useful? Dec28 comment What do correlation functions compute in CFT? @Kelly What is "moment" of the partition function? Dec28 awarded ● Nice Question Dec28 comment What do correlation functions compute in CFT? Thank you for the detailed answer providing physic background. I don't fully understand your answer, but now get a feeling about what CFT try to understand. Dec28 comment What do correlation functions compute in CFT? Thank you for the answer, Igor. I am now happy to know that holomorphicity may be interpreted as a field equation. May I ask what the fields $\phi(z)$ and $J(z)$ stands for in this context? Is $\langle0| J(z)J(w)|0\rangle$ the amplitude to observe a particle at $z$ after a particle is created at $w$ or something? Dec28 comment What do correlation functions compute in CFT? @Jeff I would rather want to know the physical interpretation. It would be nice if you could provide an answer. By the way, I don't know if there is any "purely mathematical interpretation" of correlation function. Dec28 comment What do correlation functions compute in CFT? @user1540 My question is a bit vague. I would like to know both the complex coordinates and the physical meaning of $J(z)$, and they must be related. My problem is that I don't have any intuition behind what I am computing. Dec27 comment Motivation of Virasoro algebraThanks you for letting us know the projective representation point of view. That makes sense. Dec27 asked What do correlation functions compute in CFT? Dec27 comment Motivation of Virasoro algebraI don't quite understand what you try to mean in the second comment. I would appreciate it if you could post a bit more detail as an answer. Dec27 comment Motivation of Virasoro algebraThanks for your writing "why $c=D$" above. Dec27 comment Motivation of Virasoro algebraThank you for the answer, Chris. May I ask why multiplication by the unit vector is related to the space dimension? Dec27 comment Motivation of Virasoro algebra@Abdelmalek Thanks for pointing out the typo. Dec26 asked Motivation of Virasoro algebra