Sindbad~EG File Manager

Length of proof is 8.  Level of proof is 3.
 
---------------- PROOF ----------------
 
4 [] T(x,y,ext(x,y,w,v)).
5 [] E(y,ext(x,y,w,v),w,v).
14 [] -E(xa,xb,xc,xd)|E(xc,xd,xa,xb).
22 [] -E(xa,xb,xc,xd)|E(xb,xa,xd,xc).
326 [] -congruent(xa,xb,xc,xd,xe,xf)|E(ext(xb,xc,xe,xf),ext(xb,xa,xe,xd),ext(xe,xf,xb,xc),ext(xe,xd,xb,xa)).
327 [] -congruent(xa,xb,xc,xd,xe,xf)|xa!=xb.
328 [] -congruent(xa,xb,xc,xd,xe,xf)|xc!=xb.
329 [] -congruent(xa,xb,xc,xd,xe,xf)|xd!=xe.
330 [] -congruent(xa,xb,xc,xd,xe,xf)|xf!=xe.
331 [] congruent(xa,xb,xc,xd,xe,xf)| -T(xb,xa,xa1)| -E(xa,xa1,xe,xd)| -T(xb,xc,xc1)| -E(xc,xc1,xe,xf)| -T(xe,xd,xd1)| -E(xd,xd1,xb,xa)| -T(xe,xf,xf1)| -E(xf,xf1,xb,xc)| -E(xa1,xc1,xd1,xf1)|xa=xb|xc=xb|xd=xe|xf=xe.
333 [] congruent(a,b,c,d,e,f).
334 [] -congruent(d,e,f,a,b,c).
339 [] ext(b,a,e,d)=a1.
340 [] ext(b,c,e,f)=c1.
341 [] ext(e,d,b,a)=d1.
342 [] ext(e,f,b,c)=f1.
351 [binary,333.1,330.1] f!=e.
352 [binary,333.1,329.1] d!=e.
353 [binary,333.1,328.1] c!=b.
354 [binary,333.1,327.1] a!=b.
355 [binary,333.1,326.1,demod,340,339,342,341] E(c1,a1,f1,d1).
593 [ur,331,334,4,5,4,5,4,5,4,5,352,351,354,353,demod,341,342,339,340] -E(d1,f1,a1,c1).
631 [binary,355.1,14.1] E(f1,d1,c1,a1).
644 [binary,593.1,22.2] -E(f1,d1,c1,a1).
645 [binary,644.1,631.1] $F.