Talk:Moore–Penrose inverse

message: This article is using math image forcing in almost all places.  What I mean is that e.g. A A^+A = A\,\! is used instead of A A^+A = A; the former forces the use of png images for math by the \,\! construction.
I do not like this for several reasons:
# It is ugly (note how png images do a poor job respecting the baseline).
# It is screen-reader unfriendly.
# AFAIK the wiki software has some heuristics which allows it to format math the proper way depending on the browser used for viewing, or on user preferences, which is circumvented by using \,\!.
I'll happily delete all occurrences of \,\! in this article, but I thought I'd maybe ask first :)
--- Papppfaffe (talk) 20:52, 27 April 2011 (UTC)
replies: text: I agree. — MFH:Talk 14:56, 12 February 2012 (UTC)
replies: text:  I have removed all uses of \,\!. In my browser, this made no visible difference in the entire article, which is good. I have also removed extraneous uses of \,, which in three cases made no difference and in two cases it looks better to me.  --RainerBlome (talk) 10:39, 19 December 2019 (UTC)
thread_title:  Forced math notation / images 

message: This is a page on a well-established topic and is generally well-sourced. However, one sentence in one section refers to an article under clear violation of NPOV. This sentence also uses language that reflects a general lack of neutrality. I suggest removal of this sentence.
-V madhu (talk) 17:06, 26 September 2018 (UTC)
thread_title:  Reference to article with NPOV issues 

message: Added generalization to all fields along with example. Could this be expressed more clearly? --Svennik (talk) 10:47, 27 November 2020 (UTC)
replies: text: Without having looked at this in detail, the restriction "doesn't always have a pseudoinverse" leads me to believe that that paragraph would be better suited in the article on generalized inverses. One of the salient points of the Moore–Penrose inverse is that it always exists (for R, C and B Matrices). --RainerBlome (talk) 23:52, 17 January 2021 (UTC)
replies: text:  But when it exists, it's unique, unlike generalized inverses. --Svennik (talk) 13:26, 18 January 2021 (UTC)
thread_title:  Added generalization to all fields along with example 

message: # As user:84.246.203.253 prefers (MOS:VAR !!) , others such as me prefer .Reason: it is typographically closer to  and .
# Changed also K to  in §§ Moore–Penrose inverse#Geometric construction and Moore–Penrose inverse#Rank decomposition​, because of the occurrence of A^+ in both §§ — which would be undefined if .
# Changed AB in formulas to A B, so that it is easier to change one of them by means of an editor which supports searching for whole words.
# A few typos.
–Nomen4Omen (talk) 17:48, 20 December 2020 (UTC)
thread_title:  Remark to changes of 20 Dec 2020 

message: Special:Diff/1090367874 introduced properties that can be expressed in a simple sentence, but instead using notation that is not universally understood. Syntax seems to be "A matrix is a set of tuples of coordinates (which are themselves tuples of two index values), and values in ". Please prefer to use simpler notation, and introduce the notation in the notation section. I also think that the notation is questionable, but I'm not even 100% sure I understand the author's intent.
* Special:Diff/1168148932 should have changed  to , shouldn't it?  If yes, the error could have been avoided if the local convention of using braces (\mathbb{k}) had been used in the first place. I fixed this.
* The  operator seems overloaded, meaning two different things in the same expression. Neither of these exactly matches its use ("m x n") in the notation section.
* Dimensions m and n are permitted to be zero, but this is unlikely to make sense. I fixed this.
RainerBlome (talk) 00:31, 16 September 2023 (UTC)
thread_title:  Please introduce notation 

message: There seem to be many overlapping terms in this topic which can be confusing. For example "column space" is the same thing as "image". But the term "support" is used but not defined. Please can someone knowledgeable define it? Bodger Boffin (talk) 14:33, 9 October 2023 (UTC)
replies: text: —Anita5192 (talk) 15:16, 9 October 2023 (UTC)
thread_title:  Define Support 

message: In the Definition section, it is stated that "Note that ... are orthogonal projection operators, as follows from ..."  (Sorry, copy and paste deleted the math expressions.) But I believe the conditions cited, P^2 = P, are those for "projection," not "orthogonal projection."  The Properties / Projectors section properly cites both conditions, namely P^2 =  P for projection, and, in addition, P^H = P, for orthogonal projection.
I would edit the article, but I'm not an expert in this area. QRManual (talk) 14:47, 18 April 2024 (UTC)
thread_title:  Projection vs Orthogonal Projection