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
1
vote
1 answer

Notation for $\{n\in\mathbb{Z}:n\ge m\}$ for a given $m\in\mathbb{Z}$

Is there a standard notation for the set of integers which are greater than or equal to a fixed integer $m$?
user84413
  • 27,211
1
vote
1 answer

question about Einstein summation

why is this expression valid? $ c_{i}(x_{i}+y_{i}) $ it has the index repeated 3 times instead of 2 times.
set5
  • 1,067
1
vote
0 answers

In math notation, how to indicate that one number is supposed to be appended/prepended to (or inserted in) another number as a whole?

I don't know if there exists a special, separate term for this operation in mathematics (maybe "to ascribe"?), but here is an example. Let's say I have a variable $m=2$ and I want to write it at the end of number $1$ in order to get another variable…
lyrically wicked
  • 890
1
vote
1 answer

Greek sigma symbol correct representation?

I wish to display to people that a number is a total. I have decided to use the greek symbol for sum: Σ Do I prefix or suffix numbers with this symbol? Given the total is 10. Σ10 or 10Σ
Valamas
  • 111
1
vote
2 answers

Can a parameter of a function be NULL?

Can a parameter of a function be NULL like in the example below? $ f_{AE}(t_x;i_1;i_2;p)= \begin{cases} \hfill \frac{\displaystyle\sum_{k=i_1}^{i_2} R_s(e_{c_k,t_x};a_k)}{p} \hfill & \text{if $p \neq NULL \land R_s(e_{c_k,t_x};a_k)=…
Stev
  • 15
1
vote
1 answer

Space of smooth functions with compact support.

Quick question regarding the generally accepted definition for a space. Suppose we consider the space $C_{0}^{\infty}(\Omega)$ of smooth functions of with compact support in $\Omega$, do we generally require strict containment of the support in…
guest38234
  • 13
1
vote
2 answers

Is there a language-agnostic way to formularize "if"-conditions?

How can you formularize "if"-conditions in a language-agnostic way? I'm talking about formulas like $$ x=\begin{cases} 2,&\text{ if } n \le 2 \lor m=3\\ 3,&\text{ if } n \gt 2 \land m=n \end{cases} $$ Of course, everybody in the world will…
F.P
  • 117
  • 6
1
vote
1 answer

What does the degree symbol in $K_n \subset K_{n+1}^{\circ}$ mean?

What does the degree symbol in "Let $(K_n)$ be a sequence of compact subsets such that $K_n \subset K_{n+1}^{\circ}$ mean?
Steven-Owen
  • 5,556
1
vote
2 answers

Basic question on math notation of max and min

When we write $\text{max}\left \{x,y \right \}$ and $\text{min}\left \{x,y \right \}$ then what do we actually mean? Does it mean the maximum and minimum of both the things that are inside $\left \{ \right \}$. Say $\epsilon = \text{max}\left…
OGC
  • 2,305
1
vote
1 answer

Full stop as multiplication sign

I have often seen, that users of this forum use "$.$" (full-stop) as a multiplication sign, e.g. $4.5=20$ I have thought, that this notation is the american style. But a user of this forum told me that this is not the case. Therefore my question is,…
callculus42
  • 30,550
1
vote
0 answers

Notation for compactly supported functions

I teach a course in real analysis and applications to partial differential equations in which I spend some weeks talking about Sobolev spaces. I have always used the symbol $C_0^\infty(\Omega)$ to denote the set of infinitely differentiable…
Siminore
  • 35,136
1
vote
2 answers

Notation Question $n$ $ < <$ $m$

What does the following notation mean: $n< < m$ , where $n$ and $m$ are numbers?
MATH
  • 501
1
vote
1 answer

What does $\propto$ mean in the following equation?

I have seen this question but I still have problem with the meaning of this symbol. From this book: The time-dependent angle may be defined from the components of the wave vector in order to determine its sense of rotation …
Sepideh Abadpour
  • 1,348
  • 4
  • 13
  • 24
1
vote
1 answer

What is the "T" set?

I am reading an engineering paper and it references a "T" set in the same way that one would reference the set of complex numbers with $\mathbb{C}$, or the set of real numbers with $\mathbb{R}$". What is this set? I can't find it in any list of set…
Spencer
  • 11
1
vote
0 answers

Do the natural numbers include zero? And what should we call them, with or without zero?

Possible Duplicate: Is 0 a natural number? There seems to be no consensus, although perhaps one is gathering over the centuries to say yes to the first question and identify $\mathbb{N}$ with $\omega$ : the set of finite Von Neumann ordinal…
John Bentin
  • 18,454
1 2 3
…
99 100