A little problem with Fred's note. I never gave a talk at Columbia before becoming a post-doc in September 1960. (Indeed the embedding theorems hadn't been proven by either Lubkin or me before September 1959.) But in the academic year of 1958-59 Lang was giving a course not just at Columbia but at Princeton (where I was first-year grad student) and it was devoted to category theory. But from what Sammy Eilenberg later told me, Lang was certainly broadcasting the stuff I was doing. (My undergrad honors thesis at Brown had contained the special case of the special and general adjoint functor theorems, to wit, the case where one of the two functors is an inclusion functor. I learned only later about adjoints -- the proofs for my reflective and coreflective subcategories worked without change.) Sammy often complained to me in the following years how Lang told everybody that I was the world's greatest category expert. Quoting "Fred E.J. Linton" <fejlinton@usa.net>:
...in the first-year graduate algebra course [Serge Lang] gave at Columbia during the 1958-1959 academic year...it gave me not only my first exposure too Serge Lang, and to categories, but to Saul Lubkin and Peter Freyd as well, each of whom Serge invited to give a "guest lecture" for a day (it was the era of the "race for the best embedding theorem":-) ).
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