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 is the name of this "" notation and what does it mean?

I've come across an expression from the Stanford Neural Network Course Note that looks like this: (where a, b, c are parameter vectors) What is the name of this notation "" and what does it mean / do? i.e. I guess it means "1" (one) but not…
Atlas7
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Is there a mathematical symbol I can use for "where" in this?

To solve ${x^2} - 15x + 56 = 0$ use the formula $\ x = \frac{{ - b \pm \sqrt {{b^2} - 4ac} }}{{2a}}$ where b = - 15,a = 1,c = 56. Is there a mathematical symbol I can use for "where" in this?
Michael McLaughlin
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Explain this notation: $\overline{g(x)}$

In my analysis homework, I have this expression: $$ (\cdot | \cdot): \quad C[a,b] \times C[a,b] \rightarrow \mathbb{K}, \; (f,g) \mapsto (f |g) := \int_a^b f(x) \overline{g(x)} \;dx $$ Any idea what $\overline{g(x)}$ stands for? EDIT $\mathbb{K}$ is…
fpmoo
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Notation for a Self-Map

Is there a standard notation for a self map? i.e. for a map $$f : U \rightarrow U$$ We can describe $f$ in words as a map on $U$ or a self-map on $U$. But is there an accepted mathematical notation for this that doesn't involve writing $U$ twice?…
Myridium
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big O, small o and op notations

I got really confused with these three notations and their relations. $O(n), o(n)$ and $o_p(n)$. And also if a relation like this $sup|c_n(t)-c(t)|\rightarrow0$ in P. Can we use any of the three notations mentioned above to represent it? Thanks…
emma_s
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Notation for selecting $n$ maximum entries of an array?

I have a vector $A=\left[\begin{array}{ccccc}1&2&5&4&3\end{array}\right]$ and I get vector $B=\left[\begin{array}{cc}4&5\end{array}\right]$, i.e., the maximum two elements of $A$. What could be the proper notation for representing $B$? For example…
Digi1
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What does $f(x) = f(\text{ sum of the digits of }x ) \{ \mathrm{if}( x \ge 10) \}$ $= x \{ \mathrm{if}( x \lt 10) \} $ mean?

What exactly does this notation mean when using it to define a function? $$f(x) = f(\text{ sum of the digits of }x) \{ \mathrm{if}( x \ge 10) \} = x \{ \mathrm{if}( x \lt 10) \} $$ Thanks
user7079
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What symbol is this? $\mathscr{S}$

What symbol is this? $\mathscr{S}$ \mathscr{S} I drew it on Detexify to find how to write in mathjax, but it doesn't tell me what it is... Context: "...call the resulting polyhedron $\mathscr{S}.$" I knew that it probably didn't have any specific…
suomynonA
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Meaning of double colon $::$

I recently came across the following expression regarding function composition: \begin{equation} g \circ f : A \rightarrow C :: a \mapsto g(f(a)) \end{equation} I get what this expression is trying to tell me, but I am pretty disturbed by the fact…
Jerry
  • 364
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Mathematical symbol for "indifference"

Is there any mathematical symbol for the word "indifferent". I mean that if I want to say if $x$ > 0, the machine can indifferently choose between $y$ or $z$. I want to express the last part in a mathematical notation. I know that in economics, we…
mallet
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How could I use set notation to describe this situation?

Tracts are composed of one or more parcels. There are three types of tracts, A, B, and C. There are three types of parcels, D, E, and F. Parcels of any type may or may not be leased. If at least one parcel in a tract is leased, then the tract is…
Patri
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Confusion regarding how Big O notation is used in practice

I'm trying to work through a pretty basic regular expansion problem in my textbook but I'm getting tripped up by the use of Big O notation. I understand the formal definition of Big O notation, but here it seems to be being used to denote terms on…
bones_mccoy
  • 573
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Help with this significant figures question? Confused!

The question says to give your answer to the following calculation in scientific notation with the correct number of significant figures: $(1.285 \times 10^{-2}) + (1.24 \times 10^{-3})$. The answer is $1.409 \times 10^{-2}$. Wouldn't it be $1.41…
Broadsword93
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What's the equivalent to floor(x) and ceil(x) for real numbers?

Are there equivalents to the notation of $\lfloor x \rfloor$ and $\lceil x \rceil$ that don't round to the next integer, but to a specified digit of a real number? Examples $floorReal(2.3656, 1) = 2.3$ $ceilReal(2.3678, 2) = 2.37$ Do notations for…
Foo Bar
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Is there a symbol for the first n natural numbers or the natural numbers up to n?

This seems useful but I can't find anything like it. For example, I might want to say that $\mathbb{N}_{7} = \{ 0, 1, 2, 3, 4, 5, 6 \}$ or $\mathbb{N}_{7} = \{ 0, 1, 2, 3, 4, 5, 6, 7 \}$. Is some sort of notation like that accepted?
JohnDoeVsJoeSchmoe
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