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Length of proof is 7.  Level of proof is 5.
 
---------------- PROOF ----------------
 
4 [] T(x,y,ext(x,y,w,v)).
24 [] T(xa,xb,xb).
38 [] xb!=ext(xa,xb,alpha,gamma).
77 [] xa=xp|xb=xp|xc=xp| -T(xa,xp,xc)|T(xb,xp,xc)| -sameside(xa,xp,xb).
109 [] -sameside(xa,xp,xb)|xa!=xp.
110 [] -sameside(xa,xp,xb)|xb!=xp.
114 [] sameside(a,p,b).
115 [] a=p|b=p|x=p| -T(a,p,x)| -T(b,p,x).
117 [binary,114.1,110.1] b!=p.
118 [binary,114.1,109.1] a!=p.
145 [binary,115.4,24.1,unit_del,118,117,24] p=p.
152 [binary,115.5,77.5,unit_del,118,117,117,factor_simp] x=p| -T(a,p,x)|y=p| -T(y,p,x)| -sameside(y,p,b).
170 [factor,152.2.4,unit_del,118,114] x=p| -T(a,p,x).
1501 [binary,170.2,4.1] ext(a,p,x,y)=p.
2406 [para_from,1501.1.1,38.1.2] p!=p.
2407 [binary,2406.1,145.1] $F.