Tagged Questions

Questions on the usage and meaning of words in mathematics, the names for mathematical entities, and other such questions.

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What does it mean for a function to be bounded near $\infty$?

Suppose $f(z)$ is some analytic function which is bounded near $0$. Then $f(1/z)$ is bounded near $\infty$. What exactly does that last statement mean practically? Does it mean $|f(1/z)|$ is bounded ...
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Meaning of a Logical Operator

Is it possible to know what those operator mean if they must be involved in this logicical condition? What is all the possible meaning of those two symbol if you don't know the symbol's meaning ...
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What's the difference between tuples and sequences?

Both are ordered collections that can have repeated elements. Is there a difference? Are there other terms that are used for similar concepts, and how are these terms different?
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Why were filters and nets in topology named filters and nets?

I am wondering why do mathematicians categorizes some structures and called them filters , Nets? In English, filter means: A porous material through which a liquid or gas is passed in order to ...
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Name of binary relation: if $(x, y)\in R$ then there is no $z$ such that $(y, z)\in R$

Is there a term for a binary relation $R\subset A^2$ on some set $A$ such that if $(x, y)\in R$ then there is no $z$ such that $(y, z)\in R$ ? Are there any examples of it? Are there any related ...
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What is the correct terminology to say that $\small f(x)=a+bx+cx^2+…$ can be expressed by $\small g(x)=A(1-x)+B(1-x)(2-x)+C(1-x)(2-x)(3-x)+…$

Hm, I do not even know the best formulation for my question in the header. It is not for the math but for the proper writing/terminology. I've come across the term "base change" recently but the ...
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Complementary Solution = Homogenous solution?

I have calculated solutions to homogenous equations but is the complementary solution mentioned here the same as the homogenous solution? Let's take example $y''-3y'+2y=\cos(wx)$ and now ...
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Lemma vs. Theorem

I've been using Spivak's book for a while now and I'd like to know what is the formal difference between a Theorem and a Lemma in mathematics, since he uses the names in his book. I'd like to know a ...
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Probability Term for something that defies the odds.

I'm not a mathematician; I just wandered over here from Writers SE and am hoping you guys can help. I'm writing a novel in which the theme is characters beating the odds. (It's a future dystopia, the ...
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sheaf of hyperplanes

I've got a question on terminology. In 3d, a set of planes intersecting at a point is called a bundle of planes. A set of planes intersecting along a line is called a sheaf of planes. My question ...
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Del. $\partial, \delta, \nabla$: Correct enunciation

I've come across various different symbols being pronounced as "del". What is the internationally accepted del? If not internationally, then what's the English/American(specify which one if they are ...
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What's this type of chart called?

What's the name of this type of chart?
Say $X$ is a set of subsets of some arbitrary set. Is there a name for a function $f:X\to X$ satisfying $f(A)\subseteq A$ for all $A\in X$? More specifically, is there a name for an $f:X\to X$ with $... 2answers 37 views Understanding the Lie algebra$o_{V,B}$I am learning about Lie algebras and I do not understand the following subalgebra of$\mathfrak gl_{V}$. Let$V$be a vector space and$\mathfrak gl_{V}$be the Lie algebra of endomorphisms on$V$. ... 1answer 103 views What's the usual name for this kind of integration? When I did further maths at college, we spent a couple of hours on a particular kind of integration, where the function was integrated with respect to the length of the path along the function, ... 2answers 262 views Terminology: center (of a group, of a ring, …) What is the etymology of the word "center" as used in abstract algebra, e.g. the center of a group, or of an algebra? My best guess is that it might've come from matrix algebras, where often the ... 2answers 245 views When is a calculation undefined and when is it indeterminate? I have the sense that f(x0,y0, ...) is indeterminate if the limit can be any complex number if we choose the right path to (x0, y0, ....). MathWorld and Wikedidia mention the subject, but it wasn't ... 1answer 113 views Does the subgroup$\{g\in G\,|\,o(\operatorname{Cl}(g))<\infty\}$of$G$have a name? Let$G$be a group. We can define $$F(G)=\{g\in G\,|\,o(\operatorname{Cl}(g))<\infty\},$$ where$o(\operatorname{Cl}(g))$is the order (cardinality) of the conjugacy class of$g$in$G$. This set ... 1answer 770 views Being isomorphic as representations of a group G Let$G$be a finite group. What is meant by two finite dimensional vector spaces (over$\mathbb{C}$)$V$and$W$being "isomorphic as representations of$G$"? To show that we have such an isomorphism, ... 1answer 110 views Is there a name for this homomorphism from$G$to$\operatorname{Sym}([G:H])?$Let$G$be a group and$H$its subgroup. Let$n=[G:H]$be a cardinal number. Let$C=\{aH\,|\,a\in G\}.$We have$n=\operatorname{card}(C).$We define for any$g\in G$the map$\phi_g:C\to Cby the ... 1answer 383 views Turning a Product of Events into a Product of Conditional Probabilities Is there a name for the following identity? \begin{align*} & \Pr\left(\bigwedge_{i=1}^n A_i \mid B \right)\\ &= \Pr\left(A_1 \mid B \right) \cdot \Pr(A_2 \mid A_1 \wedge B) \cdot \Pr(A_3 ... 1answer 759 views Notation in linear algebra, what are N(T) and R(T) Working through some stuff I found on the web, I came across a notation that I haven't seen in my textbooks. In this problem, T: P_4(\mathbb R)\rightarrow \mathbb R^4 is a linear transformation, ... 2answers 891 views How to pronounce “tableaux”? [closed] How do you pronounce Young tableaux? Does it sound just like its singular form? 1answer 462 views Why are modules called modules? I know that a module is a generalization of a vector space, but I would like to know why are modules called modules? Thanks for your kindly help. 1answer 97 views How to mathematically formulate and illustrate the following statement? English is not my native language and I'm trying formulate the following statement as simple and as mathematical as I can: A code is composed of a family name followed by n option(s): &... 4answers 163k views What is the formula to calculate Profit Percentage? Let cost price of an item be C, selling price be S. Assume the seller makes a profit. Then profit would be: P = S - C. Now, what is the formula for calculating Profit Percentage? P \% = \... 2answers 1k views What is usually meant by logit scale or log scale? This question is more about the math terminology than about the math itself. Say we have x = logit(p). If one says "logit scale" does he mean: the scale of p, or ... 1answer 2k views What do [] mean and what does it mean if it is used in an equation? What do the square bracket symbols mean? Are they what I hear are "sets"? And when it is in an equation, how is it interpreted? Here is an example:\dfrac{dy}{dx}[2x2+y(x)2]=50x+2y(dy/dx)=0$1answer 268 views Extension and reduction of the structure group Let$H\subset G$be a subgroup and$\pi:P\to B$be a principal$H$-bundle.$G$has a left$H$action and one can define a principal$G$-bundle$\pi':P\times_H G\to B$where$P\times_H G$is ... 1answer 131 views Ellipse: Name for the ratio$a/b$? Given an ellipse with semi-major axis$a$and semi-minor axis$b$, is there a "common" (or at least standard) name for either$\frac{a}{b}$or$\frac{b}{a}$? I keep wanting to (informally) call it ... 1answer 111 views Point travels around curve I wonder what does this mean: Point travels around curve. I try to figure out some math explanation in the book and I can't move forward because I can't understand these words. I can understand when ... 0answers 436 views Are derivative and differential the same thing? (Sorry for bad English.) Let$f:\mathbb R^n\to\mathbb R^m$,$x\in\mathbb R^n$. What is a drivative$f'(x)$? It is the linear map$f'(x):\mathbb R^n\to\mathbb R^m$,$h\mapsto (f'(x))(h)=:f&...
Let $G$ be a planar graph. We construct a graph $H$ from $G$ in the following manner : The vertices of $H$ are interior points of the edges of $G$, one on each edge. Two vertices of $H$ are joined ...