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Questions tagged [notation]

Questions on the meaning, history, and usage of mathematical symbols and notation. Please remember to mention where (book, paper, webpage, etc.) you encountered any mathematical notation you are asking about.

Before asking a question on the site, please check if you can find your answer in Earliest Uses of Various Mathematical Symbols or the book A History of Mathematical Notations.

Alternatively, a textbook or paper usually takes the time to explain the notation they're using; please remember to mention where you've seen the notation you are asking about.

12848 questions
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Denoting usage of equation - Notation

How do you notate the insertion of values in a formerly defined formula? When you have the $x,y$-tupel $(a1;b1)$ and following text: $$f(x)=mx+b \tag{1.1}$$ $$b_1=ma_1+b$$ Is there a math sign to denote "usage"?
Jan
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Why use $\forall$ instead of $\in$?

So, here are two ways to say what I interpret as the same statement: $f_i(x,y)\geq0 \hspace{0.85cm} \forall i \{0,1,2\}$ which implies that $f_0(x,y) \geq0$ and $f_1(x,y)\geq0$ and $f_2(x,y)\geq0$ but doesn't $f_i(x,y)\geq0…
joshuaheckroodt
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What is the meaning of $\Bbb R^{2+}$ in this formula

What is the meaning of $\Bbb R^{2+}$ in this formula? $$\Gamma_1=\{(z_1,z_2)\in\Bbb R^{2+}:z_1\ge z_2\}$$
Apacs
  • 39
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How to express "round up to the nearest 2" in mathematical notation?

I'm trying to solve a problem I posted here on Math SE. Part of my solution is to round up to the nearest x (e.g. 4.5 rounds up to 6 if x = 2). How do I express that in mathematical notation?
MathNewbie
  • 235
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Notation to specify the parameter that achieves a minimum/maximum?

When I write $\text{min}_x f(x)$ I always read it as "the minimum value of $f(x)$" over some given range. I am wondering, what is the standard notation for writing "the parameter that achieves a minimum (or maximum)" Eg. I have a function $f(x)$ and…
Patty
  • 787
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Notation: Subsets of elements with same function values

I have a finite set $A$ of real numbers. Then I have a function $F: \mathbb{R} \rightarrow \mathbb{Z}$ that maps real numbers to integers. I would like to split A into subsets such that for all elements in a subset, the function $F$ maps to the…
user3207838
  • 113
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Can I assume that a biologist will know what "lhs" and "rhs" mean? Or what are some other ways of indicating the left/right hand sides of an equation?

I am writing a scientific article with a few mathematical equations. Can I assume that my audience will know what lhs and rhs mean?
David LeBauer
  • 619
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Question about notation from a Theorem

Sorry if this is a simple question, but I'm unsure about what this notation means. Here is the statement I am confused about: The Perron-Frobenius Theorem: Let $A$ be an indecomposable nonnegative matrix with $\rho(A) = 1$. Denote by $r$ the…
Smeef
  • 361
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Symbol for 'implies and is not implied by'?

Is there a mathematical symbol for 'implies and is not implied by'? ie. $$\Rightarrow \land \nLeftarrow$$ Context: To provide extra emphasis in proofs with lines such as $$x = 1 \,\,\,\,\,(\Rightarrow \land \nLeftarrow)\,\,\,\,\, x^2 = 1$$
Shuri2060
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How to type 'spanning' symbol in latex

Very simple question. For a subring, submodule, subgroup, subspace of an appropriate object we often define them by the generators. In this case we say subgroup generated by $x_1,\cdots x_n$ or $$ except we don't quite use the…
Jack Yoon
  • 1,466
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Translation for $if \exists i \in [m]$ s.t. $x_i = x$

I am trying to read a book on machine learning which define the error function $hS(x)$ where $$[m] = \{1,\ldots,m\}$$ as being However I do not understand well basics math notation, would you mind helping me to understand this one, and also if you…
matel
  • 13
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Vector-matrix element-wise product notation

Suppose I have a matrix $A$ with entries $A_{ij}$ and a vector $u$ with entries $u_i$, and that I want to express matrix $C$ with entries $C_{ij} = A_{ij}u_i$ as a product of matrices or vectors and…
nayriz
  • 281
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How to read this notation?

Under the policy $\pi(\phi,a)$, the sequence of loss functions \begin{equation} L_i(\theta_i) = \mathbb{E}_{\phi,a\sim \pi(.)}[(y_i - Q_i)^2], \end{equation} is minimized, in order to train the Q-network. How do I read the $\mathbb{E}_{\phi,a\sim…
BlueMoon93
  • 255
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question about union notation

$\left\{a\right\}\cup\left\{b\right\}\cup\left\{c\right\}$ can be written as $\bigcup\left\{\left\{a\right\},\left\{b\right\},\left\{c\right\}\right\}$ can it not?
Tessera
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Describe filtering using math notoation

s is defined as $s : {1,2,3}$ To describe the function that filters values great that $a$ where $a = 2$ and multiplies result by 4, is this correct : $$ \sum_{s \in S} : [ s > a] \cdot 4$$
blue-sky
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