∀[k:ℕ]. ∀[c:ℚCube(k)]. (dim(c) ∈ {-1..k + 1-})
{ (ProveWfLemma THEN MemTypeCD THEN Auto) }
1. k : ℕ
2. c : ℚCube(k)
3. ↑Inhabited(c)
⊢ (-1) ≤ Σ(dim(c i) | i < k)
⊢ Σ(dim(c i) | i < k) < k + 1