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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Meaning of $\mathbb{R}^0$, $\mathbb{R}^{1/3}$, and $\mathbb{R}^{-2}$.

In mathematics, we take $\mathbb{R}^n$, where $n$ is a fixed positive integer, to represent the Cartesian product $$ \overbrace{\mathbb{R} \times \mathbb{R} \times \cdots \times \mathbb{R}}^{n \ \text{times}} = \left\{ (x_1, x_2, \dots, x_n) : x_1,…
Jason Ross
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What is the symbol ≙ most commonly used for in a mathematical or math-related context?

What is the symbol ≙ most commonly used for in a mathematical or math-related context? LaTeX produces the symbol with \hateq. The symbol has Unicode codepoint U+2259. The respective Unicode code chart shows it with the name ESTIMATES and the…
Lover of Structure
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What does the comma notation mean?

I am confused by the notation comma. I know that the comma means 'AND' in Set theory as gate ($a \land b=a$ AND $b$), But we write solution of equation as $x=1$, $2$ (the equation: $x^2-3x+2=0$) The question is whether $x=1,2$ is WRONG? $x=1,2$…
LeeDH
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What is a common symbol for angles and what are semantic differences?

I've just seen that LaTeX offers at least three symbols for denoting angles: $\text{\sphericalangle}:\sphericalangle ABC \\\text{\measuredangle}:\measuredangle ABC\\\text{\angle}: \angle ABC$ I think I've understood that a spherical angle is…
Martin Thoma
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For all unique notation?

Is there notation for "for all unique..."? For instance, suppose you wanted to consider all distinct $x,y$ in some set $S$. Would we type $\forall !x,y\in S$? Can we use "distinct" and "unique" interchangeably in this sense? I've never seen notation…
user59083
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Abbreviated notation for "vector normalized by its length" (unit vector)

Is there any established notation to abbreviate $\vec{x}/||\vec{x}|| = \frac{\vec{x}}{||\vec{x}||}$? Sure, this expression looks quite short already, but with a long argument such as $\vec{x} = a\cdot (\vec{b} \times \vec{c}) - (\vec{c} \cdot…
bers
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Why do lambda and pi go together?

In measure theory, we have "lambda systems" and "pi systems". Pearl's message passing algorithm has "lambda messages" and "pi messages". Is there a reason that lambda and pi go together?
Neil G
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Notation: What does this summation mean?

I need to understand what the summation below mean. I specifically do not understand the $i
Synex
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"such that" logical symbol

So, in the definition of what is a square root, $\sqrt{x}$ are all numbers $y$ such that $y×y=x$. are there any logical mathematical symbols so that the above definition can be written using logical operators only, and no natural language? Where…
Marcus Junius Brutus
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What does the notation $\twoheadrightarrow$ mean?

I don't know what this double-arrow $\twoheadrightarrow$ means!
OhMyGod
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What is $\ln 0$?

What is $\ln 0$ ? Is it $-\infty$ or indeterminate?
JSCB
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Interpretation of "not equal" notation

This will be a short question. Let $x$, $y$, $z$ be three elements from any set. Is the following: $$x \ne y \ne z \tag{1}$$ Equivalent to: $$x \ne y, ~ ~ y \ne z, ~ ~ z \ne x \tag{2}$$ Or simply: $$x \ne y, ~ ~ y \ne z \tag{3}$$ Is it even…
Thomas
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Square brackets instead of parens for functions?

Why are sometimes square brackets used to apply parameters to functions instead of the usual round parentheses? For instance, in my probability course, they use $\text{P}[X]$ to denote the probability that some event in the set $X$ comes to…
phant0m
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How to read mathematical formulas?

I'm coming from a programmers background, trying to learn more about physics. Immediately, I was encountered by math, but unfortunately unable to read it. Is there a good guide available for reading mathematical notation? I know symbols like…
Naftuli Kay
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What is the notation for a stepped range

I am searching for a notation which represents a (closed) integer range in certain steps. A step size of 4 in the interval $[-4\ldotp\ldotp 12]$ would produce: $\{-4,0,4,8,12\}$
Leander
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