Mathematics Stack Exchange
Mathematics Stack Exchange

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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Let $S$ be a set. How is $f(S) = S$ different from $f(s) = s$ for all $S$?

Usually, $f$ denotes a function, $f(x)$ is an image of $x$ under $f$. But what's $f(X)$ if $X$ is a set? edit: Please, disregard the body of this question. I had to put something here to be able to post the question.
Meshuggah
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What is the mathematical notation for the mode of a distribution?

Am writing an economics paper wherein defining a dummy variable as a taking the value one if the value of one variable is greater than the mode of another. What would be the best way to write this formally? I thought perhaps $$ Y_i=1 \mbox{ if }\,…
StephenB
  • 51
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When to use implies

I often wonder about notation and what is acceptable. I have seen many different ways of linking equations together, sometimes with just $=$ and others with $\iff$ or $\implies$. Now, I know when solving a limit or a derivative for example, you can…
Liam McInroy
  • 276
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Notation for discrete cross-correlation

Consider two real valued vectors $x$ and $y$. Suppose $x$ is $m$ dimensional and $y$ is $n$ dimensional with $n \ge m$. What is good notation for the function which returns an $n-m+1$-dimensional vector whose $i$th element is $$f(x,y)[i] =…
user66307
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Notation for an Unknown in an Equation that Represents a New Variable with Every Invocation?

If you have: a*a*a you can represent it as: a^3 Is there a similar notation to collapse a*b*c to some form: ?^3 where ? represents "a", "b", and "c" (different quantities) multiplied together?
Dennis
  • 141
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2 answers

Notation for summation while skipping elements

Suppose I have a summation like so: $\sum_{i =0}^n l^i$ Except I don't want to compute for all $0 \leq i \leq n$. I just want to compute it for the arithmetic sequence: $1, 3, 5, 7, 9...$ How do I write this in the summation notation?
Quanquan Liu
  • 391
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What is the correct way of writing this equation? Room volume (m^3) = width (m) × height (m) × depth (m)

What is the correct way of writing this equation? 1: Room volume m3 = width m × height m × depth m 2: Room volume (m3) = width (m) × height (m) × depth (m) 3: {Room volume}m3 = {width}m × {height}m × {depth}m Or something else? Thank you.
Vico
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Trying to identify mathematical symbol

I encountered this symbol in an old Adobe mathematical character set, and I'm trying to identify it. I can't find it on Wikipedia's list of mathematical symbols, and it's difficult to describe it for the purposes of a Google search. Here is an…
Channel72
  • 617
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Identification of matrix index notation

I came across this expression in the documentation for some software: $\displaystyle\sum\limits_{j=1}^c\alpha_{i*(j)k}q_j=Q_k$ Here, $\alpha$ is the element of a matrix with the rather curious index "$i*(j)k$", which the documentation describes as…
Carlton
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Is there notation for the set of all odd positive integers?

I want to denote the set of all odd positive integers. Is there a specific set notation for this?
mr eyeglasses
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A strange notation

In one of my papers I found a notation where 2 letters one under other are placed in brackets without any additional operation symbol - attached image (N m). What does this mean, is this a shortcut of summation?
user1132968
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What does this function notation mean?

My text tells me that the general term of a sequence can be looked at like a function: $ f:\mathbb{N}\rightarrow \mathbb{R} $ What does that mean translated into common english?
User1996
  • 143
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Simple notation question about brackets

Is this notation correct? I am not sure about the brackets. $x^2=4$ $x=\{-2,2\}$ Thanks in advance.
rae306
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What is " terminating reciprocals"

I meet a problem "What kinds of numbers have terminating reciprocals in base 60?", but I don't know what is "terminating reciprocals". Please help me, thanks.
6666
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formal notations

I have a problem of expressions with proper notations. If you can help me to give a formal and exact expression, it will be helpful. The specific description is Given a set of non-negative variable $c_{m,k}\in C$, there exists $\max\{c_{m,k}\}$…
user91232
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