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.

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Notation for conditional expressions

In Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I, i.e. "the LISP paper", John McCarthy introduces a notation for conditional expression as follows: $(p_{1} \rightarrow e_{1},\dotsc,p_{n} \rightarrow e_{n}…
Tianxiang Xiong
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How to denote a "boolean" (on/off, 1/0) variable in mathematics?

Is there any conventional notation for variables that can only take the value 0 or 1? (I'm looking for something of the nature of an overbar, a caret, etc.)
andreasdr
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Expanding out summation signs

I am trying to follow along in a textbook (Boas: Mathematical Methods in the Physical Sciences) and I have a problem understanding how to expand the following summation signs. (They are unrelated to each other. I just need help with understanding…
Joebevo
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Mathematics notations

When one says "a random permutation of $[n]$" what does "$[n]$" refer to? Here, $n \in \mathbb{N}\backslash\{0\}$. Also, what does a "$c\sqrt{n}$-tuple $S = (s_1, s_2, ..., s_{c\sqrt{n}})$ of elements of $[n]$ mean? As far as I know, the number of…
user90593
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Notation: meaning of {∗} ( bracket with star )

What is the meaning of the mathematical symbol $\{∗\}$? The Context is the wikipedia article on the Fock Space: Often the one particle space H is given as $L_2(X, \mu)$, the space of square-integrable functions on a space X with measure \mu The Fock…
Falafel
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Expressing through summation subscript

I am trying to define an equation to model a psychological phenomenon such as e.g.: $B=\sum_{i=1}^k (P_{ij} T_j)$ Where $B$ is boredom, $j$ is an attribute of a given situation, $i$ is a stimulus in that situation, $P_{ij}$ is the performance…
vabm
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What is the dot product of a function and a differential?

In a few theorems with integrals it looks like they are taking the dot product of a vector valued function or vector field and the differential. $\oint_C \textbf{F} ⋅ d \textbf{r}$ from here and $\int_C \textbf{F}(\textbf{r})⋅d\textbf{r}$ here for…
Corey
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Simple functional notation issue

I didn't learn functional notation very well and I'm not sure exactly where to find the answer for this so if someone doesn't mind explaining some pretty simple stuff that would be greatly appreciated: $$f(x)-g(x)=(f-g)(x)$$ What does this mean and…
Zduff
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Notation for an expression that is true for modular arguments

I am trying to write clearly and compactly that a certain coefficient, with indices $k_1$ and $k_3$ is null unless both $k_1$ AND $k_3$ are integer multiples of the integer variable $s$. Right now I have: $$t_{k_1}^{k_3} = 0 \ \ \forall \ \ k_1,k_3…
okj
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Meaning of commas in set notation

Let $X=\{ x\in X: x \text{ satisfies condition } A, x \text{ satisfies condition } B\}$. Does the comma in above set notation mean that $x$ has to statisfy $A$ and $B$ at the same time or only one of those; so that we have: $X$ is the union of…
Thomas Windisch
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Given an interval $I$, what does the notation $\overline{I}$ mean?

I have below a beginning of a theorem: If a function $f:I \rightarrow \mathbb{C}$ defined on an interval $I$ of length $p$ can be expanded to a piecewise differentiable function on $\overline{I}$, then will... What does $\overline{I}$ mean in this…
characters
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Regarding notation of functions

I have little a problem in understanding some notation, when a function is defined. It sometimes says Assume furthermore that we are given a $C^{1,2}$ function $$f:R_+\times R\to R$$ What does $C^{1,2}$ mean? This notation appear in Arbitrage…
Javed
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What does this symbol mean in math? ($Z_+$ and $Z_{++}$)

What is the difference between $Z_{+}$ and $Z_{++}$? Is the first all the non-negative integers and the second all the positive integers?
robw
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notation: 95%Ci ranges from A to B?

What is the clearest way to state that a 95% CI has a lower bound of A and an upper bound of B. Most commonly, I see: $$95\%\textrm{CI}=[A,B]$$ But this seems to imply that the CI is a vector of length two. If I were speaking very precisely, I would…
Abe
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How to mathematically phrase a logical "or" over multiple options.

I apologize if this is off topic but I think it fits. I am trying to succinctly describe a logical check for an algorithm which is a logical or. That is I want to say that we remove any cells $k$ with any grid corner $i$ that satisfies…
Andrew
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