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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4 answers

How to write down formally number of occurrences?

I want to write the following sentence formally: The sequence $S$ contains elements of the set $A$. The probability value $P(a)$ for an element $a$ is defined as the number of its occurrences in the sequence $S$, divided by the count of all its…

notation

asked Mar 10 '13 at 15:44

Spook

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1 answer

Maths symbol that looks like Sputnik

I'm doing some marking for a year 8 (12 to 13-year-old) scholarship paper and I saw this symbol that looks like the Sputnik probe and I have no idea what it is, does anyone know?

notation

asked Sep 28 '16 at 07:33

Alex Robinson

1,111

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3 answers

Notations involving squiggly lines over horizontal lines

Is there a symbol for "homeomorphic to"? I looked on Wikipedia, but it doesn't seem to mention one? Also, for isomorphism, is the symbol a squiggly line over an equals sign? What is the symbol with a squiggly line over just one horizontal line?…

notation

asked Sep 28 '11 at 16:04

james

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3 answers

The meaning of $\rightsquigarrow$ in math?

In order to write a scientific paper, I would like to use the symbol \rightsquigarrow or \leadsto which look as: $\rightsquigarrow$ or $\leadsto$ I'm wondering about the usual meaning and use of this symbol. Thanks in advance.

notation

asked Feb 18 '14 at 12:26

FraSchelle

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3 answers

Confused with the notation of functions and equations

While seeing some math stuff I realized I'm confused with some of the notation to distinguish functions and equations. I have some points where I have some doubts and would like to clear them out, would be grateful if someone could answer to all of…

notation

asked Oct 17 '19 at 00:11

Master Viewer

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4 answers

What does this double sided arrow $\longleftrightarrow$ mean?

What is $\longleftrightarrow$ used for in mathematics? I know about $\iff$ being used for "If and only if". Are they the same thing? I was watching a YouTube video that said: $$\sum^{\infty}_{n=1} {1\over n^x} \longleftrightarrow \int^{\infty}_{1}…

notation

asked Jan 18 '16 at 01:40

Max Echendu

1,489

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3 answers

What is the difference between plus-minus and minus-plus?

Possible Duplicate: What is the purpose of the $\mp$ symbol in mathematical usage? Just as the title explains. I've seen my professor actually differentiating between those two. Do they not mean the same?

notation

asked Jun 19 '12 at 20:07

drum

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3 answers

Symbol for finite

I understand there is a symbol for infinite. Is there one for finite? I searched and found there is none. How is finite represented symbolically?

notation

asked Jun 18 '12 at 12:47

orange

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5 answers

Learning to read complex math formulas

could anybody point me to a book or article where I could learn how to read formulas like this one: I have no idea what that means.

notation

asked Jun 19 '13 at 17:58

ryudice

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2 answers

Best practice for the notation of conditions in cases: 'if' vs 'for' vs ','

Consider the following three representations of the Kronecker delta function $\delta_{ij}$: $$\delta_{ij} = \begin{cases} 0 &\text{if } i \neq j, \\ 1 &\text{if } i=j. \end{cases}$$ $$\delta_{ij} = \begin{cases} 0 &\text{for } i \neq j, \\ 1…

notation

asked Oct 17 '17 at 11:31

egg

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2 answers

Notation for functions

I have a basic question about the notation for writing functions. Say that I have a function defined as $$f(x) = g(x) - 1.$$ Is it then correct to write $$ f = g -1?$$ Are there any problems with writing functions like this?

notation

asked Jun 20 '17 at 13:10

Aurantium

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3 answers

Is it possible to write a number in a base of less than 1?

Following on from this question: https://math.stackexchange.com/a/217112/45127 If we take base 10 as an example, the granularity is 1. I.e. we increment the digits in an increment of 1 until we reach 9 and then start a new column. If the base is…

notation

asked Oct 22 '12 at 11:54

BanksySan

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4 answers

What is the symbol ''$\divideontimes$'' (DIVIDE TIMES) for?

I looked "$\divideontimes$" up on Google and now I know that it's Unicode U+22c7 but when would it be used? I am guessing that $5 \divideontimes 5 = 25$ and $1$...?

notation

asked Oct 01 '14 at 16:19