Proved zadd_left_commute and zmult_left_commute to define
zadd_ac and zmult_ac. Deleted add_cong, add_kill and add_left_commute_kill as
unused. Defined zadd_simps, zminus_simps, zmult_simps and added them to
integ_ss.
#! /bin/sh
# teeinput -- start a program and log all inputs to a file
# environment variable $LISTEN specifies the file name
tee -a -i $LISTEN | $*