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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What does $\forall$ mean?

ProofWiki What does the upside-down A on this page mean? $$\forall a,b\in S: a\circ x=b\circ x \implies a=b$$
RLP
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Notation: where to put brackets around summation or product, what is the convention?

Sometimes it is necessary to place brackets around a long summation or product. If I am forced to do so, do I place them around the whole summation or product, $$\left(\sum_{n=1}^N a_n + b\right), \;\text{and }\;…
Robo
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What does the symbol $\leqq$ mean?

What does the symbol $\leqq$ mean? I am reading a paper on by Lehman on dependence, and here I find “$\ldots$we compare the probability of any quadrant $X \leqq x$, $Y \leqq y$ under the distribution $F$ of $(X,Y)$ with the corresponding…
January
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What is the mathematical notation for a group of pairwise disjoint sets?

Assume I have 4 sets: $A$, $B$, $C$, and $D$. What is the mathematical notation to indicate that all of these sets are pairwise disjoint? I can obviously type: $$A \cap B = \emptyset$$ $$A \cap C = \emptyset$$ etc. But I am looking for a more…
Kostas
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What does square subset and square union symbol mean?

I am reading a program analysis book and the author jump right into using some notations without explaining the meaning of them and now I have trouble understand the whole thing. The notations in question are: $\sqsubset$, $\sqsubseteq$,…
MathNoobe
  • 391
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How to do If and Else in math?

Hello all I would like to learn how to show if/else logic in math notation so here is the problem I'm faced with. then If R_x is in [X1, X_end] then: If R_y is f(R_x) then If R_z < C then 0 Else 1 How do I convert this into math notation ?
Wookadooma
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Is $x_1\cdot x_2\cdots x_n$ proper notation?

In a textbook I recently saw the notation $$x_1\cdot x_2\cdots x_n$$ which was intended to mean $\prod\limits_{i=1}^nx_i$. This is unappealing to me because for example one wouldn't write $$x_1+x_2\cdots x_n,$$ but rather $$x_1+x_2+\dots+x_n.$$ On…
Peter Woolfitt
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Is there a symbol for "given" in mathematics?

Is there a symbol for "given" in mathematics? For example, for the statement: Each member, $x$, of the integer sequence $f(n)$ equals the sum of the two previous members, $f(n-1)$ and $f(n-2)$, given $f(0) = 0$ and $f(1) = 1$. How do you write…
Tyler Durden
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what is the right symbol for the "max" like Pi is for product?

I have a set of variables that have a value, and i want to find the max of those values. Here is the equivalent of what I want to do with "sum" $$\sum_{j:~N_j \in U_i}~ DA_j$$ For all j subject to $N_j \in U_i$, then sum $DA_j$. Except I want a…
gnychis
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What is the name of this letter?

I found the symbol below on an article, but I don't know its name. Thanks
user200635
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Typesetting imaginary unit and bessel functions

I know that this issue has been treated in many places, but I have yet to reach something conclusive, hence I am herein seeking your help. Following the 260.3-1993 - American National Standard Mathematical Signs and Symbols for Use in Physical…
Christos Oreinos
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Notation for the last X sorted elements of a set

I have a set of ages, $\mathbb{T}=\{30, 33, 39, 40, 41\}$. I'd like to refer to the last $X$ of these ages by $\mathbb{T}^{(X)}$. So, $\mathbb{T}^{(2)} = \{ 40, 41 \}$. But how can I define this $\mathbb{T}^{(X)}$? Somehow I need to communicate,…
synaptik
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What is $B'_L$ and why is it equal to 1?

I understand all the other ones, but the $B'_L$ has me stumped. What does it mean and why is it equal to 1?
Timwi
  • 249
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Incorrect notation in math?

Does math have an incorrect notation / syntax? I don't mean writing misaligned notation (google), but when you take something like a number to powers to powers to powers, $${{2^2}^2}^3$$ (I was told this is incorrect notation by a teacher). Is it…
hit
  • 549
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Are there other ways to phrase "Let $A\in \mathbb{R}$ and $B\in \mathbb{R}$?"

Is one of these phrasings the most clear and official (something you might expect in a published paper)? Is there a better way to phrase this simple statement? Let $A \in \mathbb{R}$ and $B \in \mathbb{R}$. This seems technically correct, but feels…
Mark
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