Talk:List of mathematical functions

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Elementary functions

"Algebraic functions are functions that can be expressed as the solution of a polynomial equation with integer coefficients." Math noob here, but surely the coefficients don't have to be integers? — Preceding unsigned comment added by DamnedOwl (talk • contribs) 10:33, 22 March 2017 (UTC)[reply]

Floor function and Signum function are not elementary functions. --fil

I'm pretty sure they're not special functions either; at least I've never seen them discussed as such. (Special function has a specific connotation if not an exact definition.) Wikipedia's own special function article doesn't mention them, nor do a couple of others I looked at. http://en.wikipedia.org/wiki/Special_functions http://www.math.com/tables/integrals/specialfuns.htm
http://mathworld.wolfram.com/SpecialFunction.html --starwed

Sawtooth wave, Square wave and Triangle wave are not elementary functions either. —Preceding unsigned comment added by 88.162.139.106 (talk) 08:11, 25 March 2009 (UTC)[reply]

Periodic and transcendental functions

1. I've seen that the trigonometric functions are moved back and forth between the periodic and and transcendental functions. It's clear that they belong both, but it seems odd right now when they appear twice. Can someone suggest how and where to put them?

2. Are the inverse trigonometric functions (e.g. arcsine) formally included in trigonometric functions, or should be specified separately?

3. For Power functions, should it be specified that the power is not integer? Yoshigev 14:33, 24 February 2006 (UTC)[reply]

Periodic and transcendental are overlapping categories indeed. What's wrong with including a function in both?
Right: xⁿ is not transcendental for integer n (and how about rational n?)
As far as I gather from the definitions square root isn't transcedental

we should add a group algebraic functions −Woodstone 22:06, 24 February 2006 (UTC)[reply]

Yes, I think we should add algebraic functions, and below it put: the polynomials, rational functions, square root, and rational powers (radical functions).
All periodic functions are transcendental (except functions like f(x)=a), so I think they should be put them under "transcendental functions".
Since all the functions are either algebraic or transcendental, I think that we should also put the functions at the beginning of the section into these sub-sections.

—Yoshigev 21:40, 25 February 2006 (UTC)[reply]

What's more, hyperbolic functions are periodic too (of imaginary period however). Xedi 13:06, 30 March 2006 (UTC)[reply]

Odd mix in categories

The first few categories of functions are a rather odd grouping. We might distinguish properties definable based on:

set theory
a single operation (+ or *)
a group structure
two operations (both + and *)
on a field structure
the real numbers
the complex numbers

−Woodstone 12:19, 25 February 2006 (UTC)[reply]

I have now made a first try at more structure. Since there is a lot of overlap between categories it is not fully satisfying yet. Your comments (and edits) are welcome. −Woodstone 22:15, 25 February 2006 (UTC)[reply]

I think "Function classification property" should only list properties, so the functions in "Relative to a field" should be under elementry functions. The same with "Number theoretic functions" that should be in a different section.

Do you think that it's important to distinguish between "real" and "real (or complex)"? —Yoshigev 00:26, 26 February 2006 (UTC)[reply]

I am not sure about "Relative to a topology". I found that there are two definitions for continuity: Continuous function, Continuous function (topology). I don't think that the normal continuity should be under topology, so maybe in the same category with monotonic function, under "real analysis" (see List of real analysis topics). —Yoshigev 15:18, 26 February 2006 (UTC)[reply]

I have tried to classify the functions according to the minimum requirements on their domain (and codomain). Continuity can be defined on a topological space. Every metric space (like the real or complex numbers) is also a topological space. The continuity in such a space is the same as the one defined for the induced topology (the article mentions this vaguely).

The functions under "field" do not require the function to be real/complex. Perhaps the number theoretic functions can be mover under this heading (but I'm not expert enough to be sure).

The functions under "real" cannot be (usually are not) defined for the complex plane.

As far as I have checked, all functions under "special" are real/complex functions. −Woodstone 15:45, 26 February 2006 (UTC)[reply]

Right now it looks like a jumble of all the functions. First of all, I think we should divide between function properties (like "Injective function") and function classes (like "Polynomials").

After that, I suggest that the article will have this sections:

Elementry functions (like polynomials and trig). Divided to:
- Algebraic
- Trancendental (with maybe what is now under "Relative to an integral domain", but I'm not sure).
Special functions (Gamma, Elliptic...)
Function properties (with the division of Woodstone).

I think most readers would look for elementry functions in this aricle so they should appear first.

—Yoshigev 14:51, 1 March 2006 (UTC)[reply]

It's already much better than it was before, but you're welcome with further improvement suggestions (and actions). A few remarks to your remarks: most of the "special" functions and the "trig" functions are transcendental, so your the grouping proposed above needs some work. I'm not so sure what was meant by "integral domain" (I called it a "ring" structure). Perhaps we should go back to the "number theory" group. −Woodstone 16:32, 1 March 2006 (UTC)[reply]

I've made the change in the sectioning. But there are still functions that I don't really know where to put.

I think that most functions under "Basic special functions" are elementary, but I'm not sure. If somebody can sort them, and find a nice heading for them...
I think that "Relative to an integral domain (number theory)" should be put under "special functions", but again I'm not sure.

—Yoshigev 18:59, 1 March 2006 (UTC)[reply]

I moved some specific functions (such as the number theoretic ones) into "special functions", and some lines that were actually properties of functions (differentiable, homomorphic, analytic) into the categories. I think there is no real definition of "basic" or "elementary" functions, that is just a school term. −Woodstone 21:35, 1 March 2006 (UTC)[reply]

The article define elementary function by giving a list of operation that construct them. I didn't find any name for them, and didn't want to give the whole list, so I wrote "basic operation". I put all the other functions under "special" although some of them don't fully qualify the term (like Absolute value).

You moved the following functions to the properties section but I think they are specific functions (not a class): Dirichlet function, Question mark function, Weierstrass function.

—Yoshigev 10:35, 2 March 2006 (UTC)[reply]

I agree that "Question mark function" and "Weierstrass function" are specific, but "Dirichlet function" is a class. Feel free to move accordingly. −Woodstone 12:19, 2 March 2006 (UTC)[reply]

Should this even be here?

This list is so completely incomplete it shouldn't even be here.

A list like this could by definition never be complete. That does not mean that it is of no interest. If important named functions are missing, why not add them? −Woodstone 21:37, 4 October 2006 (UTC)[reply]

Yes this should definitely be here, I needed a list of various common mathematical functions for demo purposes, and I expected Wikipedia to have such list and it did indeed, and was helpful.--92.107.251.225 (talk) 21:41, 1 May 2011 (UTC)[reply]

The purpose of such encyclopedic entires would be to start at the notable. That a cohesive representation comes as a process to this venture, if possible, is just a nice side effect. Yet lacking the possibility for completeness does not preclude the focus on notable functions from establishing an encyclopedic entry on this topic of some kind of pertinence. This therefore, would be my justification. Nagelfar (talk) 05:57, 3 September 2011 (UTC)[reply]

Dawson function

The Dawson function is listed twice (under both "Antiderivatives of elementary functions" and "Other standard special functions") 141.228.106.135 (talk) 09:15, 18 April 2008 (UTC)[reply]

I've removed the second mention. Gandalf61 (talk) 09:44, 18 April 2008 (UTC)[reply]

Legendre functions under "Bessel functions and related functions"

I don't think Legendre functions should appear in this section.

Legendre functions are Gauss hypergeometric functions, whereas Bessel functions are confluent hypergometric functions. Very different beasts, even though there does exist relations between them. HowiAuckland (talk) 12:58, 2 November 2009 (UTC)[reply]

Mixing our Categories

I think a problem with this list (which seems to be echoed in the conversations above (years ago!)), is that we're mixing apples and oranges. "Special functions" are special because they tend to have their own name and notation, but they can also be categorized as algebraic or transcendental. Thoughts on clarifying this? Ethan Mitchell (talk) 02:15, 19 August 2011 (UTC)[reply]

List of impossible operations in maths

Is there any possible way to quantify known impossible operations/calculations in the various forms of mathematics? For example, although anything divided by zero is itself, it is impossible to turn this operation and divide zero by that anything: the operation is non-computable. Could there be an exhaustive list of such impossibilities? I believe they may be of interest, personally, due to their philosophical implications. Nagelfar (talk) 05:52, 3 September 2011 (UTC)[reply]

Nagelfar, you have it somewhat backwards. Anything divided by zero is undefined; zero divided by anything except zero is zero. As for making a list, I think there are too many such situations to be worth enumerating, and many of them are specific to particular fields of numbers. For instance, the square root of a negative number is undefined for the real numbers, but it is defined for the complex numbers. Ethan Mitchell (talk) 15:52, 4 September 2011 (UTC)[reply]

I believe what you're looking for is Indeterminate form#List of indeterminate forms. Robo37 (talk) 18:49, 4 September 2011 (UTC)[reply]

Hmm, that's a little more specific, but it's nice. Ethan Mitchell (talk) 12:58, 5 September 2011 (UTC)[reply]

Relation to Wikipedia article List of special functions and eponyms

What is the relation between this list and the list at List_of_special_functions_and_eponyms. There is quite a mismatch between the special functions section of this article and that list, but maybe I've just misunderstood the contents of those lists? tjajab (talk) 11:18, 30 December 2012 (UTC)[reply]

Piecewise

Shouldn't this list include piecewise functions? — Preceding unsigned comment added by Niedzielski (talk • contribs) 15:38, 7 August 2015 (UTC)[reply]

Graphs

This list is a great overview. It would be even more useful if each function included a small graph picture to help readers understand and build intuition about the differences and characteristics of each. Many articles already have an exemplary leading image that could be used. — Preceding unsigned comment added by Niedzielski (talk • contribs) 15:42, 7 August 2015 (UTC)[reply]