Signed Involutions Avoiding 2-Letter Signed Patterns

Abstract.

Let I _n be the class of all signed involutions in the hyperoctahedral group ${\mathfrak{B}}_n$ and let I _n (T) be the set of involutions in I _n which avoid a set T of signed patterns. In this paper, we complete a further case of the program initiated by Simion and Schmidt [6] by enumerating I _n (T) for all signed permutations $T \subseteq {\mathfrak{B}}_2$.