New classes of examples satisfying the three matrix analog of Gerstenhaber's theorem
Abstract
In 1961, Gerstenhaber proved the following theorem: if k is a field and X and
Y are commuting dxd matrices with entries in k, then the unital k-algebra
generated by these matrices has dimension at most d. The analog of this
statement for four or more commuting matrices is false. The three matrix
version remains open. We use commutative-algebraic techniques to prove that the
three matrix analog of Gerstenhaber's theorem is true for some new classes of
examples.
In particular, we translate this three commuting matrix statement into an
equivalent statement about certain maps between modules, and prove that this
commutative-algebraic reformulation is true in special cases. We end with ideas
for an inductive approach intended to handle the three matrix analog of
Gerstenhaber's theorem more generally.