The fact that, given a string of three adjoints, the first is full and faithful iff the third one is, can be found in Barry Mitchell's 1960 book. ************************************************************ F. William Lawvere Mathematics Department, State University of New York 244 Mathematics Building, Buffalo, N.Y. 14260-2900 USA Tel. 716-645-6284 HOMEPAGE: http://www.acsu.buffalo.edu/~wlawvere ************************************************************