... the notions category and functor were not formulated or put in print until the idea of a natural transformation was also… — Saunders Mac Lane Categories Copy Share Image
. . . the membership relation for sets can often be replaced by the composition operation for functions. This leads to an… — Saunders Mac Lane Alternatives Copy Share Image
The standard "foundation" for mathematics starts with sets and their elements. It is possible to start differently, by axiomatising not elements of… — Saunders Mac Lane Categories Copy Share Image
. . . in one sense a foundation is a security blanket: If you meticulously follow the rules laid down, no paradoxes… — Saunders Mac Lane Arise Copy Share Image