YES Consider the TRS R consisting of the following rewrite rules: minus(minus(x)) -> x minux(+(x,y)) -> +(minus(y),minus(x)) +(minus(x),+(x,y)) -> y +(+(x,y),minus(y)) -> x The TRS R is transformed (by dropping rewrite rules whose left-hand sides contain a function symbol which does not occur in any right-hand side) into a TRS R' which is empty. Hence R is terminating. __________________________________________________________________ TTTbox (0.003 seconds) - April 13, 2007 Source file - /home/ami/mkorp/Testbench/tpdb-3.2/TRS/SK90/4.01.trs