Some Examples in the Realization of Symmetry

I don't think I have much to teach this audience about string theory as such. What I will do, that I hope is useful, is discuss a few phenomena that have come up in my recent work which are in some way connected to fundamental issues regarding the realization of symmetry in quantum mechanics. My strong impression is that the fundamental symmetry of string theory, or whatever string theory is evolving into, has yet to be fully elucidated; in trying to do so, it may be well to have the possibility of unusual realizations in mind. Also, the examples I will be considering involve in simple low-dimensional gauge eld theories of a kind very similar to those often arising in world-sheet or membrane studies.