Re: On UA-CAT Workshop at MSRI - Empty Carriers

Bill Rowan says that -

...To me, a _type_ is an N-tuple of sets S_n, where elements of S_n are n-ary basic operations.

"Signature" is used for this notion (or many-sorted generalizations) often enough that I feel it could be standard. Steve Vickers. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++