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
# xlisten -- start a program in one window and create a listener window
# environment variable $LISTEN specifies the file name
#create the file!
date > $LISTEN
xterm -geo 80x10+0+0 -T Listener -n Listener -e tail -f $LISTEN &
sleep 2
xterm -geo 80x45+0-0 -e teeinput $* &