Questions tagged [reference-request]
This tag is for questions seeking external references (books, articles, etc.) about a particular subject. Please do not use this as the only tag for a question.
22,155 questions
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Ideal of maximal minors is radical when rank never drops by more than 1 [Reference request]
Let $R := \mathbb C[x_1,\dots,x_d]/J$ be an affine domain which is the coordinate ring of the affine variety $X = V(J) \subseteq \mathbb C^d$. Let $M \in R^{m\times(n+1)}$ be a matrix with entries ...
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Looking for authors/papers in GGT involving piecewise isometries, free group actions, and twisted Ihara zeta functions
I am working on a project that combines ingredients from geometric group theory and spectral graph theory, and I would appreciate references (papers, authors, or survey articles) that study anything ...
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Reference for the formula for conformal change of sectional curvature
Let $(M, \tilde{g})$ be a Riemannian manifold and let $g:=e^{2u}\tilde{g}$ be a conformal change. I'm trying to find a resource (ideally a book, or a paper where it's mentioned or derived) for the ...
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Continuity of surface curl
Question
Let $\Omega\in\mathbb{R}^3$ and $\Gamma=\partial\Omega$ its boundary. For any point $\mathbf{x}\in\Gamma$, let $\mathbf{n}_\mathbf{x}$ be the outward unit normal to $\Gamma$ at the point $\...
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Where to find Nardin's lecture notes on stable homotopy theory?
There are lectures on YouTube "Introduction to stable homotopy theory" by Denis Nardin . Apparently, these are recordings of a course given at University of Regensburg in 2021. The lecturer ...
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+50
Seeking generalizations of an Airy Integral
Some crude numerical experiments led me to stumble upon the amusing result that $$\int_{0}^{\infty} \frac{1}{\operatorname{Bi}(t)^2}\, dt = \frac{\pi}{\sqrt{3}}$$
where $\text{Bi}(x)$ is an Airy ...
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Function spaces, uniformities, and k-spaces
I'm looking for a resource that covers the interplay between function and uniform spaces and k-spaces. All the texts I've seen so far cover one or two of the three, but never the full combination in ...
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Ramanujan's work on the central factorial numbers
The central factorial numbers are described on OEIS sequence A008955. Among the references, "Ramanujan's notebooks, part 1" (edited by Bruce Berndt) is listed. Upon checking this source, I ...
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Meromorphic Connections on an Elliptic Curve
Let $E$ denote an elliptic curve over $\mathbb{C}$. I would like to consider meromorphic connections on the trivial line bundle $O_E^{\oplus r}$ with regular singularities occuring at some finite set ...
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reference for explicit examples of modular flow of weights
I am trying to learn operator algebra with the view of using them in concrete cases.
So I am looking for references where I can find specific computations on specific example cases, to understand the ...
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Can “points” of objects be defined without assuming the category has a terminal object?
For a category $\mathcal{C}$, for an object $C$ in $\mathcal{C}$ call a morphism $p: C \to C$ a “(generalized) point” of $C$ if
$p$ is idempotent, i.e. $p \circ p = p$.
$p$ is “maximally non-mono”, i....
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Distinct Penrose prototiles up to translation
I have the following basic question which I couldn't find through a search online. The descriptions of the Penrose prototiles using either the kite and dart or the thin and thick rhombus, say that ...
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Understanding lax natural transformations and adjunctions between strict 2-functors
I'm relatively new to higher category theory, and although I am familiar with "regular" category theory, I am having some trouble understanding the terminology and definitions used here.
For ...
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Finest possible refinement of a topology that does not alter the Krull dimension
While I was thinking about some problem in algebraic geometry I came up with the following construction, and I am asking myself if this has a name.
A (conventional) Google search yielded no results ...
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References for a probability law [closed]
Consider a symmetric simple random walk starting at $0$ and denote by $p_{n,k}$ the probability the walk occupes $k$ at time $n$. Denote also $q_n=\left(q_{n,k}\right)_{k\geq 0}$ defined by
$$
q_{n,k}=...
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many example of rings [closed]
I'm studying commutative ring theory from Hideyuki Matsumura's book, but it's so abstract that I try to come up with lots of concrete examples on my own---for instance, classifying commutative ...
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Standard names of functions defined by generalizing the power series of trigonometric and hyperbolic functions?
For integers $m$, $n$ such that $m>n\ge0$, define functions
$$
\begin{align}
h_{m,n}\left(z\right) &= \sum_{k=0}^{\infty}{\frac{z^{m\cdot k+n}}{\left(m\cdot k+n\right)!}} \\
g_{m,n}\left(z\...
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Isomorphism between two measure spaces; reference request for Rohlin (1952)
As part of the proof for Theorem 1 of Kamae et al.'s paper, "Stochastic inequalities on partially ordered spaces,"Stochastic inequalities on partially ordered spaces," the following ...
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204
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Clean version of inequality for $\Gamma(z)$ - known?
Let $z=x+i y$, $x\geq 1/2$. Is the following inequality true?
$$|\Gamma(z)|\leq (2\pi)^{1/2} |z|^{x-1/2} e^{-\pi |y|/2}$$
If you allow a fudge factor such as $e^{\frac{1}{6|z|}}$ on the right side, ...
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Product formula for resultant
The Wikipedia page for Resultants gives the definition of the Resultant as the determinant of the Sylvester matrix. It then goes on to state the characterising properties of the Resultant, all of ...
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1
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326
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What is the origin and interpretation of this piecewise formula for Rule 54?
I'm researching the properties of the single-cell evolution of ECA Rule 54 and its connection to the Collatz conjecture.
The MathWorld page for Rule 54 1 and OEIS A118108 2 both present (or are ...
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Books on Abstract Algebra [duplicate]
I am looking for a book covering topics in algebra, specifically in rings and modules. I am a graduate student, so I do not want a very basic book. I have taken a look at the book by Dummit and Foote, ...
6
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Can regularization (Abel/Borel) of a divergent derivative series tell us about $f'(x)$?
Question.
If $f(x) = \sum f_n(x)$ is a continuous function, and its formal derivative series $g(x) = \sum f_n'(x)$ diverges at a point $x_0$, but is summable (via Abel, Borel, etc.) by some ...
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1
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Finitistic projective dimension of commutative rings of finite weak global dimension
For a commutative (not necessarily Noetherian) ring $R$, define the following two quantities
$$fpd(R):=\sup\{\operatorname{pd}_R(M) | M \text{ is a finitely presented }R\text{-module of finite ...
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1
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Attribution for Metrization Theorem
Let $f:X \rightarrow Y$ be a continuous surjection with $X$ a compact metric space and $Y$ a Hausdorff space. Then $Y$ is metrizable.
Does this theorem have a name? Who first proved it? Just ...