# Talk:Linearity

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One of the 500 most frequently viewed mathematics articles.

The linearity of the function f(x)=mx+c over the reals is controversial.

Let's get a closer look: all entities in Reals; just c may be 0...
Superposition is not always satisfied:
f(y+z)=m(y+z)+c is equal to f(y)+f(z)=my+c+mz+c=m(y+z)+2c iff c=0.
Homogeneity is not always satisfied:
af(x)=a(mx+c)=amx+ac is equal to f(ax)=amx+c iff c=0.

jimmer_lactic

I've added that that's a different usage of the term linear. I hope that helps! -- Oliver P. 22:02 5 Jun 2003 (UTC)

Not true for all finite fields that superposition imples linearity: just for the prime fields.

Charles Matthews 06:37, 10 Oct 2003 (UTC)

## Linearis?

I thought linear came from "linea" (line). 62.189.34.9 20:53, 30 December 2005 (UTC)

## multimedia linearity and non-linearity

Can you assist me in what is linearity and non-linearity when talking about multimedia contents, please?

--- Linearity in multimedia or "narrative linearity", means that there's only one path from the beginning of the story to the end. We imagine it progresses in a "straight line". In a computer game on the other hand, the path may branch out. You may get into the castle by knocking down the guard, climbing in a window or bribe your way in. There may also be more than one ending. Based on your choices, perhaps the evil king is overthrown, perhaps he convinces you to support him, perhaps you die.

This "non-linearity" is not purely a multimedia feature. A sci-fi book series was published in the 70's or 80's where you jumped to different pages depending on your choice of actions.

I leave it to the main contributors to incorporate this into the main text.

Would be nice to see a page describing terminal based linearity, independent linearity, and zero based linearity.

## Maths rating and dab

I've added a rating for the maths content of this page. The other content should probably be moved out and linked via Linear (disambiguation). Geometry guy 15:54, 18 May 2007 (UTC)

I definitely agree that the non mathematical applications of linearity should be moved elsewhere. The discussions of art and military strategy don't fit. This is an encyclopedia not a dictionary and we should divide terms accordingly, and not group them simply because they are the same word and loosely related ideas. — Preceding unsigned comment added by 69.169.175.170 (talk) 21:20, 17 June 2012 (UTC)

## Boolean functions

A recent edit to Linear feedback shift register brought it to my attention that Linear#Boolean functions has no citation. A "linear" function on Z/2Z could mean linear as in Linear function#Analytic geometry, in which case both T=even F=odd and F=even T=odd are linear, or linear as in Linear function#Vector space, in which case only F=even T=odd is called linear and T=even F=odd is called affine. Can anyone dig up a citation for which is the accepted definition of "linear"? --Damian Yerrick (talk | stalk) 00:49, 3 August 2011 (UTC)

As a response to that edition of mine, I googled for references and found it ambigus! The following exerts from two arbitrary sources show both definitions:
* The function f is linear if f(x1,...,xn) = ⊕xi for some S ⊆ {1,...,n} [1]
* The non-linearity of f is the minimum of the distances between f and any aﬃne function. [2]
First one only identifies XOR as a linear function that is according to the linearity in vector space. The second one accepts any affine transformation. Algebraic linearity in vector space is the first idea that we assume for definition of linearity for bolean functions. But when I was studying coding and came across that LFSR article in wikipedia, I found that in many sources for binary codes and functions the condition of affinity is regarded as linearity as it is sufficient for the definition of linear codes and functions such as linear feedback shift register. As I am not a mathematician, decision is up to specialist editors. --slash (talk) 23:48, 7 August 2011 (UTC)

## Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was: moved to Linearity. Favonian (talk) 11:09, 14 February 2012 (UTC)

LinearLinearity — This article addresses the property of linearity and its effects on objects that instantiate that property. Thus, I think the article should be moved to "linearity", with "linear" redirecting there. (Currently, the situation is the reverse.) Augurar (talk) 06:46, 7 February 2012 (UTC)

### Survey

Feel free to state your position on the renaming proposal by beginning a new line in this section with `*'''Support'''` or `*'''Oppose'''`, then sign your comment with `~~~~`. Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's policy on article titles.
• Support; article titles should be nouns where possible. Powers T 15:17, 7 February 2012 (UTC)
• Support. In complete accordance with WP:NOUN, as has already been mentioned. I can't think of any reason not to change it. BlindMic (talk) 02:11, 10 February 2012 (UTC)