With any finitely generated presentation (pi) = of a group G, one can associate a formal language WP(,0)((pi)), the reduced word problem of (pi), consisting of all words on the generators and their inverses which are equal to the identity of G but have no proper prefix equal to the identity. A general problem, then, is to determine what the nature of the reduced word problem implies about the structure of the group G, or, conversely, how the properties of G affect WP(,0)((pi)). ; The simple languages form a class of prefix-free languages properly contained in the class of context-free languages. Simple languages can be accepted by one-state deterministic pushdown automata which read an input symbol at every step in a computation. The main results of the thesis are: ; Theorem. A finitely generated presentation (pi) of a group G has a simple reduced word problem if and only if there are only a finite number of simple closed paths passing through each vertex in the Cayley diagram of (pi). ; Theorem. A group G has a presentation with a simple reduced word problem if and only if G is the free product of a finitely generated free group and a finite number of finite groups. ; Made available in DSpace on 2014-12-14T13:09:52Z (GMT). No. of bitstreams: 1 8203480.pdf: 2129536 bytes, checksum: 470dcb09d22e97b91c16b509fb2ca804 (MD5) Previous issue date: 1981 ; Embargo set by: Seth Robbins for item 68368 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs ; Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs ; U of I Only ; 77 p. ; Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.