At: list quo choice211111111 1. q: 2. 0 < q 3. E: q*q*Prop 4. Refl(q*;x,y.x E y) & Sym x,y:q*. x E y & Trans x,y:q*. x E y 5. x,y:q*. Dec(x E y) 6. q = 0 7. x: q* 8. y: q*
(nil E nil) nil = nil q* By: Analyze 4
THEN
Unfold `refl` 4 Generated subgoal: