Left inverse implies inverse in finite dimensional algebra
3301
If $AB = I$ then $BA = I$
19683
Is a semigroup $G$ with left identity and right inverses a group?
109217
Invertibility of the Product of Two Matrices
24441
Inverse of a matrix is expressible as a polynomial?
42467
Inverse of an invertible triangular matrix (either upper or lower) is triangular of the same kind
46698
Showing a set is closed under inverses
120911
Clarification on proof: Order of left cosets equal
80996
A canonical construction proving $\left|HK\right| = \left|H\right|\left|K\right| / \left|H \cap K\right|$?
102935
Trace and determinant of composition of a left-multiplication and a right-multiplication on a space of matrices
62077
Prove that if $W_1\subseteq V$ finite-dimensional, then there is $W_2\subseteq V$ such that $V=W_1\oplus W_2$
143517
Isomorphisms Between a Finite-Dimensional Vector Space and its Dual
2995
A finite dimensional algebra over a field has only finitely many prime ideals and all of them are maximal
115120
Finite dimensional $C^*$-algebras
112407
Set of left cosets is a group
21243
Kaplansky's theorem of infinitely many right inverses in monoids?
107900
A ring which has many distinct left inverses
151752
Example of a linear operator on some vector space with more than one right inverse.