from the pep as to why not using a type that defines _mul_ as matrix multiplication : " The result is a strong consensus among both numpy developers and develop

from the pep as to why not using a type that defines _mul_ as matrix multiplication : " The result is a strong consensus among both numpy developers and developers of downstream packages that numpy.matrix should essentially never be used, because of the problems caused by having conflicting duck types for arrays " looks to me like an issue with python lack of static type checking. if you need to define an operator every time two types conflict, you're in for a long list...