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 this notation mean $\{a_k\}_{k=i}^n$?

What does this notation mean $\{a_k\}_{k=i}^n$? I saw it in sites talking about sequences but there was no explanation of what it meant. E: I reviewed the other post, this is not a duplicate, and the chosen answer described what I asked.
YoTengoUnLCD
  • 13,384
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Square bracket notation in equation

I'm attempting to understand a paper[1] on contracting geometry for computer graphics. I have an undergraduate Physics degrees to give some indication of my experience, though that was 6 years ago now. I'm stumbling on a basic part as I'm…
MichaelJones
  • 123
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Powers of powers. Is there a single interpretation of this notation

Prompted by another question on this site is this notation clear and unambiguous $$x^{y^z}$$ One answer there seems to imply the meaning is $$x^{(y^z)}$$ Mathcad seams to agree with this making $2^{3^2} = 2^9 = 512$ On the other hand my Casio…
Warren Hill
  • 3,092
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What is the meaning of $:s$ after a mathematical symbol?

I started to read a book about regression analysis, and I faced this latex notation: $e_i$:s, where $e_i$ is a residual. What is the meaning of "$:s$"?
Kim
  • 143
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1 answer

How to insert Gothic letters in Word?

I do not manage to find in any of the options provided by Word the real Gothic letters used my German mathematicians in their original works. Noe even under the two "gothic" rubrics. just some sparse cases, which do not help me at all. Could…
Javier Arias
  • 2,033
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Precedence of exponentiation

The set of functions from a set $X$ to a set $Y$ is denoted $Y^X$. Now a question about precedence of operations: Should I write $X^{(Y^Z)}$ or $X^{Y^Z}$ is enough?
porton
  • 5,053
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How do I describe summations across sets of data?

Assume that there are several geographical regions and within each region there may be many buildings. Buildings may or may not be created and destroyed from time to time hence the requirement to capture the total building area at a point in time…
Ryan Taylor
  • 143
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3 answers

Symbol to denote the angle between two points

Let $p = (0,0)$ and $q = (1,1)$ be two points. I would like to denote the angle between these two points ($45^\circ)$. I took a look at the lists of symbols, and the symbols $\angle$ and $\measuredangle$ are used to denote angles, but usually when…
user206695
  • 129
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I've been told that writing $x\equiv a,b,c \pmod d$ is abuse of notation, is it really?

I've been told that writing $x\equiv a,b,c \pmod d$ is abuse of notation, and that I should always write: $$ x\equiv a\pmod {d}\text{ or }x\equiv b\pmod {d}\text{ or }x\equiv c\pmod {d} $$ How true is this?
YoTengoUnLCD
  • 13,384
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2 answers

Why do they use absolute value symbols for $|z|=r$ considering any number squared is positive?

Am I right in saying that the absolute value symbols act like a function such that if $x$, for example, is $x<0$ then $x=-x$ In other words $x$ will be positive regardless of what value you give to $x$, right? In which case, isn't $|z|$ always…
Thomas Winkworth
  • 641
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How to refer a block in an image?

I have an image $I$ with size $X,Y$. I want to refer to a varticle stripe of the image between column $S_1$ and $S_2$. In matlab we write it as, $B = I(:,S_1:S_2)$ But how to write in mathematical notation ? Thanks in advance.
user3563929
  • 311
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How to formulate a theorem about bijections between several sets

I have several sets $A_i$ and bijections between them. (As stated in my theorem) no composition of these bijections produces a permutation of $A_i$ not equal to identity. So every bijection is identified by the pair of sets between which it acts. It…
porton
  • 5,053
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In notation for argmin

I saw this notation for $\in$ -- I'm assuming this means "defines", right? $$\hat{\theta} \in \underset{\theta}{\operatorname{argmin}} \dfrac{1}{2} \sum_{j=1}^n (\theta^T x^j - y^j)^2$$ Does anyone have a reference for a description of the $\in$…
pyrrhic
  • 459
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2 answers

Linear transformation notation question

Well the question is pretty basic, but I am learning math on my own. And I cannot understand the notation of linear transformation. I understand what linear transformation is, its properties and what not. I could not find the answer elsewhere. What…
YKY
  • 125
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1 answer

Meaning of the mapping

I am reading basic sets. In the section of sesquilinear mapping, I came across this mapping $f: X \to X^*$ i.e $x \ $ maps to $ (x|.)$ Here I know $X$ is a function space, I guess $X^*$ stands for its dual. $(|)$ is inner mapping. My question: …
Prashanth
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