Index: mttroot/mtt/lib/reduce/fix_c.r
==================================================================
--- mttroot/mtt/lib/reduce/fix_c.r
+++ mttroot/mtt/lib/reduce/fix_c.r
@@ -12,7 +12,9 @@
 
  %% Special cases
  FOR ALL x LET pow(x,0) = 1$
  FOR ALL x LET pow(x,1) = x$
 
+OPERATOR fabs$
+FOR ALL x let abs(x) = fabs(x)$
 
 END$