Let formula _ 538 and formula _ 539 be two valid representations . Let formula _ 540 be a linear map such that formula _ 541 for all formula _ 171 Then the following is irreducible :
Let formula _ 538 and formula _ 539 be two irreducible representations . Let formula _ 540 be a linear map such that formula _ 541 for all formula _ 171 Then the following is valid :