Talk:Generalized inverse

Article needs examples
This article could be improved if someone knowledgeable of the subject would insert a section with examples, preferably of all types of generalized inverse addressed in the article.—Anita5192 (talk) 01:58, 4 February 2017 (UTC)


 * I inserted examples of some types of generalized inverse. I still think it would be best to have an example of each type.—Anita5192 (talk) 16:54, 11 October 2017 (UTC)

The external link does not work
The external link does not work: Article 15A09 in: 15A09 Matrix inversion, generalized inverses in Mathematics Subject Classification, MathSciNet search — Preceding unsigned comment added by Sohale (talk • contribs) 21:51, 10 March 2017 (UTC)


 * The dead link is now removed.—Anita5192 (talk) 23:13, 10 March 2017 (UTC)

Simple computational mistake at an example
In the example of the matrix with a right inverse, there should be a typo. 1(-17/18)+2(-2/18)+3(12/18) is not equal to 1. Hovakhshatra (talk) 14:22, 21 June 2020 (UTC)


 * The (3,1) entry of matrix is 13/18, not 12/18. Saung Tadashi (talk) 14:59, 21 June 2020 (UTC)

Inverse of other semigroups (or rings) in example
Since the article is mainly about generalized inverses of matrices (only a single phrase in the introduction talks about the generalization to semigroups), this example feels out of place there. Saung Tadashi (talk) 00:17, 29 September 2020 (UTC)


 * This article should be renamed, so that its title clearly states that it is about matrices, while the general semigroup notion may be treated in a separate article.
 * Alternatively, the material on matrices may be moved into a subsection while the general semigroup definition and generic results may be highlighted in the introduction and promiment initial parts.
 * I am inclined to go this latter route. What do other colleagues think?
 * Filozofo (talk) 04:25, 29 September 2020 (UTC)


 * Agreed. In my opinion, however, the former route is a better option for now. Saung Tadashi (talk) 05:41, 29 September 2020 (UTC)

"Penrose Conditions" section is removed, "Types" reorganised
I removed the "Penrose Conditions" section [], as it was highly redundant. The definition of I-inverse was merged into the "Types" section, which was also slightly reorganised. Further, I removed the claim that


 * there are an infinite number of $$I$$-inverses for a given $$I$$ with less than 4 elements

because it is obviously false. $$A^+$$ is also $$A^{(1,2)}$$, but is uniquely defined. In any case, a corrected statement would be more suitable in a separate article on I-inverses. — Preceding unsigned comment added by AVM2019 (talk • contribs) 20:12, 13 May 2022 (UTC)