In this paper, we define and determine the p-regular subspace of symmetric Nakayama algebras. We also determine the 2-regular subspaces of algebras of dihedral and semidihedral type with two simple modules. The importance of these calculations is that any block with cyclic defect group is derived equivalent with a symmetric Nakayama algebra and any block with dihedral or semidihedral defect group and two simple modules is derived equivalent to some algebra of dihedral type and semidihedral type, respectively.

p-regular subspaces, Nakayama algebras, algebras of dihedral type, algebras of semidihedral type.