Peter Freyd claims that Hassler Whitney defined natural transformation in a 1938 paper. I no longer have access to Math. Reviews (except by going to McGill, which I have done only once in the last four years) so I cannot supply a reference.

You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message.

View group files | Leave group | Learn more about Microsoft 365 Groups