Questions tagged [terminology]

Questions on the usage and meaning of words in mathematics, the names for mathematical entities, and other such questions.

7,493 questions
Filter by
Sorted by
Tagged with
21 views

Conventions for distinguishing the two senses of an ultrafilter on X

Are there any well-established conventions to distinguish the two senses of being an ultrafilter on a set $X$ (when $X$ happens to be equipped with an ordering)? This ambiguity is confusing at first; ...
12 views

What is the correct term for an unnormalized mean of a function?

I want to report statistics for a region of interest $[x_0, x_1)$ of a function $f(x)$. As a concrete example, consider $f$ to be the spectrum seen by a radiation detector, such that $x$ has units of ...
39 views

How is it called percent with base one?

When we are referring to something that is a percentage (base 100). We talk in these terms: There is 30 percent of water It has 15 percent of fats But, when we are just representing these values in ...
43 views

Does the operation $(A\times B) \cup (B\times A)$ have its own name?

I use such an operation a lot in a computer program I write and I was wondering if it has its own mathematical name. That's all. I was looking for "commutative cartesian product" and for ...
38 views

What is the categorical-theoretical generalization of order-embeddings and downsets?

NB: even though this question's longish setup gives the impression that it is about the theory of ordered sets, in fact it is really more general than that. The setup here serves only as the ...
22 views

Name for the result of characterizing isomorphism of linear mapping between vector spaces?

Let $V, W$ be two finite dimensional vector spaces and $E = \{e_1,\dots,e_n\}$ the basis of $V$. I do know that $T:V \to W$ is an isomorphism if and only if the image $T[E]$ is a basis for $W$. But is ...
93 views

How is this integral operation called? $\langle f(x),\phi(x)\rangle = \int_{-\infty}^{\infty}f(x)\phi(x)dx$

Please, can someone tell what is the name of this operation in the context of Fourier analysis? $$\langle f,\phi \rangle := \int_{-\infty}^{\infty}f(x)\phi(x) \,{\rm d}x$$ And what is the meaning ...
51 views

Name for topology defined by order

Consider a topology on $\mathbb{R}$ that includes the following sets: $\varnothing, \mathbb{R}, (a,\infty), [a,\infty)$ for any $a\in \mathbb{R}$. Does it have a name? Postscript. There is right/...
50 views

Is being directly negatively proportional same as being inversely proportional?

If I have the proportionality $$x\propto-y$$ It suggests that x increases with $-y$ and since there's a negative symbol present it would mean that the lower the value of $y$ the higher the value of $x$...