active fact X mark if zero X s 0 prod X fact p X active add 0 X mark X active add s X Y mark s add X Y active prod 0 X mark 0 active prod s X Y mark add Y prod X Y active if true X Y mark X active if false X Y mark Y active zero 0 mark true active zero s X mark false active p s X mark X mark fact X active fact mark X mark if X1 X2 X3 active if mark X1 X2 X3 mark zero X active zero mark X mark s X active s mark X mark 0 active 0 mark prod X1 X2 active prod mark X1 mark X2 mark p X active p mark X mark add X1 X2 active add mark X1 mark X2 mark true active true mark false active false fact mark X fact X fact active X fact X if mark X1 X2 X3 if X1 X2 X3 if X1 mark X2 X3 if X1 X2 X3 if X1 X2 mark X3 if X1 X2 X3 if active X1 X2 X3 if X1 X2 X3 if X1 active X2 X3 if X1 X2 X3 if X1 X2 active X3 if X1 X2 X3 zero mark X zero X zero active X zero X s mark X s X s active X s X prod mark X1 X2 prod X1 X2 prod X1 mark X2 prod X1 X2 prod active X1 X2 prod X1 X2 prod X1 active X2 prod X1 X2 p mark X p X p active X p X add mark X1 X2 add X1 X2 add X1 mark X2 add X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 active 1 fact 1 mark 1 if 3 zero 1 s 1 0 0 prod 2 p 1 add 2 true 0 false 0 INNERMOST ./TRS/TRCSR/inn/ExIntrod_Zan97_iGM.trs