## Z4test.txt     check of P-Q pairs
#  if following X** =0, then the relation EPQE holds
with(DEtools):
read "equations.txt":
read "Z4PQ.txt":

z4pq:=proc(A,B,EE)  
        return(factor(mult(EE,A,[dx,x])-mult(B,Z4,[dx,x]))):  end proc:

 X0p1n:=z4pq(PA0p1n,QA0p1n,subs({A0=A0+1,A1=A1-1},Z4)): lprint(%):
 X0n1p:=z4pq(PA0n1p,QA0n1p,subs({A0=A0-1,A1=A1+1},Z4)): lprint(%):
 X0p1p:=z4pq(PA0p1p,QA0p1p,subs({A0=A0+1,A1=A1+1},Z4)): lprint(%):
 X0n1n:=z4pq(PA0n1n,QA0n1n,subs({A0=A0-1,A1=A1-1},Z4)): lprint(%):

 X0p2n:=z4pq(PA0p2n,QA0p2n,subs({A0=A0+1,A2=A2-1},Z4)): lprint(%):
 X0n2p:=z4pq(PA0n2p,QA0n2p,subs({A0=A0-1,A2=A2+1},Z4)): lprint(%):
 X0p2p:=z4pq(PA0p2p,QA0p2p,subs({A0=A0+1,A2=A2+1},Z4)): lprint(%):
 X0n2n:=z4pq(PA0n2n,QA0n2n,subs({A0=A0-1,A2=A2-1},Z4)): lprint(%):

 X2p3n:=z4pq(PA2p3n,QA2p3n,subs({A2=A2+1,A3=A3-1},Z4)): lprint(%):
 X2n3p:=z4pq(PA2n3p,QA2n3p,subs({A2=A2-1,A3=A3+1},Z4)): lprint(%):
 X2p3p:=z4pq(PA2p3p,QA2p3p,subs({A2=A2+1,A3=A3+1},Z4)): lprint(%):
 X2n3n:=z4pq(PA2n3n,QA2n3n,subs({A2=A2-1,A3=A3-1},Z4)): lprint(%):