IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html
At:
l member decomp221 1. T : Type
2. T List
3. u : T 4. v : T List
5. x:T. (xv) (l1,l2:T List. v = (l1 @ [x] @ l2))
6. x : T 7. (xv)
8. l1,l2:T List. v = (l1 @ [x] @ l2)
l1,l2:T List. [u / v] = (l1 @ [x] @ l2)