An algebraic structure with non-unique inverses?
103695
Prove Inverses not need be Unique if Associativity fails
151251
A simple algebra that is not semisimple
143051
Inverting noninvertible elements in a bigger ring.
135641
Algebraic independence of exponentials
37182
If an element has a unique right inverse, is it invertible?
39334
Non-degenerate bilinear forms and invertible matrices
157765
What would a Cayley table of inverse semigroup look like?
143629
Looking for insightful explanation as to why right inverse equals left inverse for square invertible  matrices
115502
Analogue of the Cantor-Bernstein-Schroeder theorem for general algebraic structures
110014
Right Inverse for Surjective Function
103014
Is the real number structure unique?
76110
Proving that the zero vector is unique
151729
Existence of a unique polynomial
107900
A ring which has many distinct left inverses
145481
Extended Euclidean Algorithm for Modular Inverse
57515
Similar matrices and field extensions
125719
Multiplicative inverse of a complex number.