Sindbad~EG File Manager

Length of proof is 5.  Level of proof is 4.
 
---------------- PROOF ----------------
 
52 [] Col(xa,xb,xa).
132 [] -R(xa,xb,xc)|R(xc,xb,xa).
153 [] -perp(xa,xb,xp,xq)| -Col(xa,xb,xp)| -Col(xa,xb,xq).
156 [] xa=xb| -Col(xa,xb,xd)| -perp(xa,xb,xc,xd)|perpAt(xa,xb,xd,xc,xd).
209 [] -perpAt(y,z,x,y1,z1)| -Col(y,z,u)| -Col(y1,z1,v)|R(u,x,v).
216 [] a!=b.
217 [] Col(a,b,p).
218 [] Col(a,b,q).
220 [] Col(a,b,c)| -R(c,p,q).
221 [] perp(a,b,c,p).
640 [binary,221.1,156.3,unit_del,216,217] perpAt(a,b,p,c,p).
642 [binary,221.1,153.1,unit_del,217] -Col(a,b,c).
1862 [binary,642.1,220.1] -R(c,p,q).
2597 [binary,1862.1,132.2] -R(q,p,c).
4296 [ur,209,218,52,2597] -perpAt(a,b,p,c,x).
4297 [binary,4296.1,640.1] $F.