| n < valid-group-nodes(gndx) ⊦ n < # gndx |
φ([]) ∧ (∀ gndx, gnd. φ(gndx) → φ(gndx + gnd)) ⊦ φ(gndx)
⊦ (∀ n, gndx. [] = gndx ∧ n < valid-group-nodes(gndx) → n < # gndx) ∧ (∀ gndx, gnd. (∀ n, gndx1. gndx = gndx1 ∧ n < valid-group-nodes(gndx1) → n < # gndx1) → (∀ n, gndx1. gndx + gnd = gndx1 ∧ n < valid-group-nodes(gndx1) → n < # gndx1))
Used terms: λ gndx0. ∀ n, gndx. gndx0 = gndx ∧ n < valid-group-nodes(gndx) → n < # gndx, gndx