Question 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.

learn more… | top users | synonyms

6
votes
1answer
37 views

Is there a standard notation for the product from right to left?

I am considering a product of the matrices $(A_i)_{1\leq i\leq n}$ in reverse order $$P=A_nA_{n-1}\dots A_1,$$ and I was wondering if there was a standard notation for it, like ...
8
votes
1answer
262 views

Bourbaki and set inclusion

Which notation ($\subset$ or $\subseteq$) was preferred by Bourbaki for set inclusion (not proper)? A side question: Was the notation for subset one of the many notations invented by Bourbaki?
6
votes
2answers
122 views

What is the meaning of $\mathbb{R}\setminus\{0\}$?

This is used in many posts related to functions and googling it doesn't help. What does this mean? $\mathbb{R}$ should stand for all Real numbers.
1
vote
1answer
40 views

In set theory, what do the subscripts $A_1,A_2,\dotsc,A_n$ mean? [on hold]

How are subscripts used in set theory, for example, In set theory, what do the subscripts $A_1,A_2,\dotsc,A_n$ mean?
0
votes
0answers
15 views

Notation: column/row projection function for matrix-like objects

If we have a $n$-tuple $\mathscr x$ $$\mathscr x := (x_i)_{i\in n}=(x_0,x_1,\ldots,x_{n-1})\in \prod_{i\in n}X_i$$ where $(X_i)_{i\in n}$ is an indexed family of sets and $x_i\in X_i$. We can ...
0
votes
0answers
21 views

Question about bilinear and quadratics form

I'm reading this book: Geometry of algebraic curves by Cornalba, Harris etc. At page 289 there is an excercise where the authors define a quadratic form $Q:V \times V \rightarrow \mathbb{C}$ taking ...
0
votes
1answer
37 views

Math notation clarification

I'm working on learning more about logistic regression and I came across an equation with some confusing notation that I've never seen before: $$ \frac{\delta}{\delta \theta_{y'}^{(j)}} l(\theta) = ...
0
votes
0answers
11 views

Alternative single-letter notations in statistics

I'm learning about statistics, and a thing that is difficult for me is the common use of multi-lettered variables and functions. For instance Standard Error of $\beta$ is written $SE(\beta)$ and the ...
11
votes
7answers
1k views

Is an empty parenthesis a valid mathematical expression? [on hold]

Is using an empty parenthesis valid? For example, $15+()=15$. What is the meaning if it is valid? I need an academic reference to validate this.
0
votes
1answer
26 views

Vector notation for shifting the elements of a vector

I'm looking for a suitable notation to express a "shift operator" which shifts all elements of a vector forward and sets the first element to zero, e.g., $$\begin{eqnarray*} (1,1,0,1) & ...
0
votes
2answers
47 views

Use of brackets around the integrand

Quick notation question: When using brackets after an integral sign, should the brackets enclose just the integrand or everything - the integrand and the differential, i.e. is it: $$\int ...
3
votes
3answers
66 views

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 $f(n-2)$, ...
0
votes
0answers
13 views

Questions regarding notation (multiple variables, rounding)

I am calculating the coordinates of the Center of Gravity for a 3D volume using the following pseudocode (where A denotes the dimension length and cogA denotes the COG for that dimension) ...
1
vote
0answers
16 views

Complex exponential argument to a function

In many texts on signal processing, the following notation is used to describe the Fourier transform of a discrete time signal $x$: $$ \hat{X}\left(e^{j\omega}\right) = ...
1
vote
4answers
66 views

What does $T:V\to W$ mean in vector spaces?

What does the sign $\to $ mean in contexts like: "show $T:V\to W$ is an isomorphism" or "if $T:V\to W$ is a linear transformation"...
2
votes
2answers
43 views

Sigma Notation multiple sigma

I'm an engineer students, I want to now the runtime of loop inside loop, I get the calculation in sigma notation like the picture above. Can somebody explain to me how sigma inside sigma can be like ...
1
vote
1answer
18 views

How to denote a function of all but one parameter (notation question)

Say I have $n$ variables, $x_1,\dots,x_n$ and $n$ functions $f_i$ such that $f_i$ is a function of $x_1,\dots,x_{i-1},x_{i+1},\dots,x_n$, but not $x_i$. Is there a more compact way of denoting this ...
3
votes
2answers
20 views

notation for Sumation of Sumation for only for odd iterations

I need to write a summation in summation whether the inner summation should iterate from one through all odd numbers to the teration of the outer summation which goes from 1 to $\infty$... Something ...
-2
votes
0answers
32 views

What does R[-a,a] represent?

More precisely: $f \in R[-a,a]$. All I could find was related to the symbol $\mathbb R$, but I have never seen it in this particular constellation, and even if it stood for "$\mathbb R$", I wouldn't ...
0
votes
1answer
32 views

How to notate the final element in a sequence?

I'm having troubles putting this in to words here, but here it goes: If I have a sequence of numbers, called $A$ where $A$ is a sequence of numbers that don't seem to have a pattern, how can I notate ...
1
vote
1answer
36 views

It is okay to have a conditions in a summation limit that depend on the current value of another summation

this is one of those things that I know how to do in a programming environment but not sure how it translates into mathematics. I'm trying to express a sum so that it is easily visible that certain ...
1
vote
0answers
26 views

Seeking after notation for two objects equal up to a constant

Sometimes we want to express that two objects are equal up to a constant but there is no need to keep writing out the constant or constants. For example, often times the constant or constants involved ...
0
votes
2answers
31 views

$\wedge$ in set builder notation

Wikipedia says to use $\wedge$ in set-builder notation like $\{x \,:\, x > 3 \wedge x \neq 10\}$. However, I prefer to merely seperate predicates by a comma. Which notation is more common?
2
votes
3answers
90 views

What set does $\mathbb W$ denote?

What set does $\mathbb W$ denote? I know this may horribly lack context, but I've seen multiple times on M.SE $\mathbb W$ used in some fairly elementary context I think.
1
vote
0answers
52 views

What's the difference between $Df$ and $Tf$?

I'm reading Michael Shub's Global Stability of Dynamical Systems. In chapter 4, he defined hyperbolic set and said the splitting $E^s$ and $E^u$ are $Tf$ invariant. So I assume this $Tf$ is the ...
1
vote
3answers
45 views

Help With Notation In Fermat's Last Theorem

The following is the notation for Fermat's Last Theorem $\neg\exists_{\{a,b,c,n\},(a,b,c,n)\in(\mathbb{Z}^+)\color{blue}{^4}\land n>2\land abc\neq 0}a^n+b^n=c^n$ I understand everything in ...
2
votes
0answers
29 views

Where can I learn more about the “else” operation / “else monoid”?

(The set of natural numbers $\mathbb{N}$ starts at $0$ for me.) Let $X$ denote a set, and define $X_\bot = X \uplus \{\bot\}.$ Let $\mathbf{else}$ denote the binary operation on $X_\bot$ defined as ...
4
votes
1answer
64 views

Need Help Understanding Notation With Functions

Original picture: LaTeX approximation: $$f\color{blue}{\substack{(x)\\x\to\infty}}=\pm\sqrt{\frac{(x^2+x)^3}{\pi}}.$$ What does the notation highlighted in blue mean? I understand that ...
1
vote
1answer
22 views

Representing Several IF statements inside a FOR loop in Math Notation

I wish to correctly represent several IF statements within a for loop in math notation. The FOR loop can be represented as: ...
1
vote
0answers
54 views

How to write the family of sets whose elements are the sets in a sequence of sets

I am wondering, given a sequence of sets $( X_n )$, how do we write the corresponding family of sets whose elements are the sets in the sequence? Of course, the same question applies to nets as well. ...
1
vote
0answers
20 views

Notation for the set of all integer partitions

I'm working on a project that involves that set $P = \{\{n_1, \ldots, n_k\} \mid k \in \mathbb{N}, n_i \in \mathbb{N} \text{ and } n_1 + \cdots +n_k = n\}$ of all integer partitions of a number $n$. ...
0
votes
1answer
35 views

Meaning of $t \mapsto \phi_t(x)$

The context may well be of assistance: Consider a differential equation $x'=f(x)$. Assume that $f:\mathbb R^n\to\mathbb R^n$ is continuously differentiable. Denote by ...
0
votes
1answer
27 views

How's this inertia called?

Let $E/F$ be an algebraic extension. Let $L_1,L_2$ be algebraically closed fields and $\sigma_1:F\rightarrow L_1,\sigma_2:F\rightarrow L_2$ be field monomorphisms. Define ...
1
vote
2answers
77 views

What does ''$\le$'' mean here?

What does ''$\le$'' mean here? Do you know the meaning of $\le$ in the second last line in the text below? The sequence $0\to N \to M \to M/N \to 0$ is exact, so by Problem 5, the sequence $0 ...
0
votes
1answer
16 views

Conway polyhedra notation calculator?

I recently read about Conway polyhedra notation, and I want to experiment with it. Are there any programs that take the notation, and output a representation of the shape?
0
votes
2answers
27 views

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 ...
0
votes
1answer
72 views

Which one of the following logical propositions is to be preferred?

I'm trying to update the symbolism of Giuseppe Peano's "Arithmetices Principia", to make the translation freely available. Might I ask you, which of the following might be a correct mathematical ...
1
vote
1answer
41 views

In Ring Theory, does a 'power' of a morphism represent composition?

Say there is a ring homomorphism, denoted by $\theta$. If the notes use the expression $\theta^2$, then are they referring to the composition of the $\theta$ homomorphism with itself?
1
vote
0answers
19 views

Is there a standard notation for $(p_i-k)(p_{i-1}-k)(p_{i-2}-k)\cdots$ where $k$ is a small positive integer

For $k=0$, there is: $p_i\# = (p_i)(p_{i-1})(p_{i-2})\cdots(5)(3)(2)$ For $k=1$, there is: $\varphi(p_i\#) = (p_i-1)(p_{i-1}-1)(p_{i-2}-1)\cdots(5-1)(3-1)(2-1)$ Is there any other notation that ...
2
votes
2answers
52 views

The mysterious $\dot{H}^{-1}$ notation.

I have encountered the $\dot{H}^{-1}$ notation in one of the SIAM Journal on Mathematical Analysis articles. It appears to be standard (or at least not uncommon) to use this one in the field, since ...
3
votes
1answer
74 views

What does the notation $\mathbf{R}^\mathbf{R}$ mean?

I was reading the Princeton Review of GRE math subject test (4th edition), and one question was (page. 251) Example 6.24 Is the ring $\mathbf{R}^\mathbf{R}$ an integral domain? ...
1
vote
2answers
53 views

Notation issue - Asymptotic behaviour: is $\sim$ too restrictive?

As a student I am completely unable to understand unambiguously what is meant by a notation such as $$f \sim g $$ when in Physics the behaviour of two functions at infinity is evaluated. I found a ...
1
vote
2answers
71 views

Differential $dx$

I have some trouble understanding a thing. I will reproduce two texts from two different books. In the first, the author defines the function $T:\mathbb{R}\longrightarrow \mathbb{R}$, ...
0
votes
1answer
40 views

Equation that defines multi-dimensional polynomial

In two-dimensions a complete n-th degree polynomial is given by $P_n(x,y) = \sum_{k=0}^{n}\alpha_kx^iy^j \qquad i+j \leq k \qquad (1)$ . However, now I am dealing with the following two-dimensional ...
5
votes
1answer
83 views

What does a single-line superscript left arrow mean?

I'm pretty sure it's a limit but I haven't been able to find any page explaining this notation (see below). It's from a paper on block maxima. 3 out of 5 occurences: $V=(-1/logF)^\leftarrow$ (p.4) ...
3
votes
2answers
27 views

Set Notation help?

If $A=\{a_1,a_2,\dots,a_7\}$ and we want to know how many $3$ element subsets exist in $A$, would we simply use ${7\choose3}=35$ on a calculator, or does this notation not account for the empty set, ...
2
votes
2answers
56 views

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 ...
0
votes
1answer
14 views

Argmax as the parameter of a function?

Let $P = \{p_1,\dots,p_n\}$ and $Q = \{q_1,\dots,q_n\}$ be two sets of points and $d(p,q)$ a distance function between points. Given an element $p_k$ I would like to know which is the maximum distance ...
1
vote
1answer
27 views

Notation for a statistic, or function of a random variable

A statistic is a function of random variables, so it is also a random variable. Suppose we have a collection $X = (X_1, X_2, \dots, X_n)$, where $X:\Omega \to \mathcal{X}^n$. There are two common ...
1
vote
3answers
37 views

Strict ceiling and floor notation

The normal ceiling and floor functions, denoted $\lceil x \rceil$ and $\lfloor x \rfloor$ respectively, refer to the smallest integer greater than or equal to $x$, and similar for the floor function. ...