Re: Linear notation

Date: Fri, 27 Dec 91 19:40:24 GMT
To: Vaughan Pratt <pratt@cs.stanford.edu>, types@theory.lcs.mit.edu

PLEASE DONT use \oplus for par - it is standard notation for the additive
connective (both with and plus, which coincide) in linear algebra.

Exercise for the reader.  With and plus (and their respective units) coincide
IF AND ONLY IF the objects carry an internal additive structure with respect to
which all maps are linear - ie the objects are modules (the unit for tensor
serves as the "ring" - in fact an (internal) "rig" in the sense of Lawvere -
it does not have negation).