Sindbad~EG File Manager

Length of proof is 6.  Level of proof is 2.
 
---------------- PROOF ----------------
 
4 [] T(x,y,ext(x,y,w,v)).
5 [] E(y,ext(x,y,w,v),w,v).
256 [] -E3(xa1,xa2,xa3,xb1,xb2,xb3)|E(xa1,xa3,xb1,xb3).
272 [] -sameside(xa,xp,xb)|xb!=xp.
320 [] 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.
322 [] sameside(a1,b,a).
323 [] sameside(c1,b,c).
324 [] sameside(d1,e,d).
325 [] sameside(f1,e,f).
326 [] E3(a1,b,c1,d1,e,f1).
327 [] -congruent(a,b,c,d,e,f).
332 [] ext(b,a,e,d)=a1.
333 [] ext(b,c,e,f)=c1.
334 [] ext(e,d,b,a)=d1.
335 [] ext(e,f,b,c)=f1.
343 [binary,322.1,272.1] a!=b.
362 [binary,323.1,272.1] c!=b.
381 [binary,324.1,272.1] d!=e.
400 [binary,325.1,272.1] f!=e.
419 [binary,326.1,256.1] E(a1,c1,d1,f1).
638 [ur,320,327,4,5,4,5,4,5,4,5,343,362,381,400,demod,332,333,334,335] -E(a1,c1,d1,f1).
639 [binary,638.1,419.1] $F.