If $A$ is a G-graded algebra then one can define on it a color involution, i.e. a bijective linear map preserving the grading such that the image of a product of two homogeneous elements is defined through a bicharacter of the group G. Color algebras are strictly related with color Lie and Jordan algebras.
Does exist a classification of simple (associative) algebras with color involution? Is there at least a classification of color involutions on matrix algebras?