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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How should one interpret a double slash, //?

Example usage I've seen: $x^2 / (y // z)$ Context: I recently started learning some fundamental electrical engineering, where I saw I calculated the power doing $vs² / (r1 + ron + ron // ron+r2)$
user50849
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Is there a notation for "open subset"

I very often have to write something like: $\exists U,V\subseteq M$ where $U,V$ are open, but there's no short hand for it. On my written notes, I do tend to write something like: $\exists U,V\mathop{\subseteq}_\text{open}M$ is there a common short…
Alec Teal
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Should I use different parenthesis in calculations?

I was taught in a school that one should denote the order of computations by different brackets like $2\cdot \{3+[2\cdot (8+9)]\}$ Do the teachers taught me wrong as for example the notation $\{\}$ is used in sets and $[]$ in matrices and in…
notsure
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$\times$ as symbol for multiplication, how common is this?

I never encountered the $\times$ symbol denoting multiplication (of real numbers or real-valued functions) since middle school until I found it recently in the measure theory notes by D H Fremlin. Since it seems to me that this author writes in a…
fweth
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Is there a notation for $f(x,y) - f(y,x)$?

Suppose we have a function $f(x,y)$ in two variables. Is there an operator on the function, say, $$([]f)(x,y) = f(x,y) - f(y,x)?$$ In other words, I'm looking for a commutator in terms of function arguments.
Peteris
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What's the point of dropping the multiplication sign before the parenthesis

What's the point of dropping the multiplication sign before a parenthesis? Sure,2(5+5) is shorter than 2*(5+5) - but I prefer readability before shortness - especially when someone else will be reading my calculations. Is there something that I am…
Zar
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Notation for a "conditional" set

Is there any commonly used short notation for the following? $A_n = \begin{cases} \{a_n\}, & \text{if $n$ is odd} \\ \emptyset, & \text{if $n$ is even} \end{cases} $ I'm looking for something like $A_n = \{a_n\}_{[\text{$n$ is odd}]}$ that will…
Hrant Khachatrian
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When is Leibniz' notation for derivatives useful?

So Lagrange's $y'$ and Leibniz' $\frac{d}{dx}y$ seems to be the two most common notations for differentiation, but it seems puzzling to me that there are two notations for this. I've been taught Lagrange's notation, and haven't really used Lebniz'…
Frank Vel
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Notation For the $n$th Prime

What is the standard notation for the $n$th prime? How would I notate the prime that is $n$ more or less than the $n$th prime? I have seen notation for the $n$th prime on various webpages, but I am not so clear on how to type it or how to use it in…
Jeffrey Young
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Is there a shorthand for 'for some x'?

'For all x' = $\forall x$, but what's a convenient shorthand for 'for some x', or 'atleast one x'? $\exists$ doesn't always seem to fit the context. For example "Find $z$ such that $xz < y$ for some $y$".
Benjamin Lindqvist
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Is there a symbol, or abbreviation for coefficient of x

Doing some binomial expansions with algebra where I need to equate different coefficients together but don't know what to write: [Coefficient of $x^3$] = _ $k=+1.5$
jaccacake
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Notation $(a,b)$ for $]a,b[$.

Is there any logic or justification for the notation $(a,b)$ to represent $]a,b[$? To me this notation is very ambiguous and confusing because it looks like a couple of numbers and not an interval. Thanks.
idm
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How to explain Borel sets and Stieltjes integral to beginner maths student?

The problem is that I know by the definition what Borel sets and Stieltjes integral are but I'm not good to explain in layman terms what they are. Is there easier answer that "write down the definitions until you have reduced everything to the…
student
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Math 'equal to?' symbol

My teacher used the following symbol: $\boxed{\overset{\wedge}{=}}$ We had to write down a vector equation, and he said my direction vector $\begin{pmatrix}6\\2\\2\end{pmatrix}$ could be simplified to $\begin{pmatrix}3\\1\\1\end{pmatrix}$ since…
rae306
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Mathematical Notation questions reading SLAM papers

I'm working through a pair of papers on Simultaneous Localization and Mapping and I'm having trouble with some of the notation as I lack some formal math education. The papers can be found here:…
munk
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