Sindbad~EG File Manager

Length of proof is 15.  Level of proof is 4.
 
---------------- PROOF ----------------
 
4 [] T(x,y,ext(x,y,w,v)).
25 [] -T(xa,xb,xc)|T(xc,xb,xa).
26 [] T(xa1,xa1,xb1).
29 [] -T(xa,xb,xc)| -T(xa,xc,xd)|T(xb,xc,xd).
32 [] -T(xa,xb,xc)| -T(xa,xc,xd)|T(xa,xb,xd).
33 [] -T(xa,xb,xc)| -T(xb,xc,xd)|xb=xc|T(xa,xb,xd).
37 [] T(xa,xb,ext(xa,xb,alpha,gamma)).
38 [] xb!=ext(xa,xb,alpha,gamma).
60 [] xa=xb| -T(xa,xb,xc)| -T(xa,xb,xd)|T(xb,xc,xd)|T(xb,xd,xc).
92 [] T(a,b,d).
93 [] T(a,c,d).
94 [] -T(a,b,c).
95 [] -T(a,c,b).
128 [binary,92.1,25.1] T(d,b,a).
209 [hyper,29,92,4] T(b,d,ext(a,d,x,y)).
267 [binary,93.1,25.1] T(d,c,a).
356 [hyper,29,93,4] T(c,d,ext(a,d,x,y)).
398 [binary,94.1,25.2] -T(c,b,a).
405 [ur,32,26,94] -T(a,b,a).
427 [binary,95.1,25.2] -T(b,c,a).
850 [ur,29,128,398] -T(d,c,b).
870 [ur,32,92,405] -T(a,d,a).
1074 [ur,29,267,427] -T(d,b,c).
1300 [ur,33,37,38,870] -T(d,ext(a,d,alpha,gamma),a).
7829 [binary,209.1,25.1] T(ext(a,d,x,y),d,b).
13127 [binary,356.1,25.1] T(ext(a,d,x,y),d,c).
79731 [hyper,60,7829,13127,unit_del,1074,850] ext(a,d,x,y)=d.
80182 [para_from,79731.1.1,1300.1.2] -T(d,d,a).
80183 [binary,80182.1,26.1] $F.