IF YOU CAN SEE THIS go to http://www.cs.cornell.edu/Info/People/sfa/Nuprl/Shared/Xindentation_hack_doc.html
At:
append split2 T:Type, L:T List, P:(||L||Prop).
(x:||L||. Dec(P(x)))
(i,j:||L||. P(i) i<jP(j))
(L_1,L_2:T List. L = (L_1 @ L_2) & (i:||L||. P(i) ||L_1||i))