Enumerating isoclinism classes of semi-extraspecial groups.

We enumerate the number of isoclinism classes of semi-extraspecial p-groups with derived subgroup of order p(2). To do this, we enumerate GL (2, p)-orbits of sets of irreducible, monic polynomials in F-p[x]. Along the way, we also provide a new construction of an infinite family of semi-extraspecial groups as central quotients of Heisenberg groups over local algebras.