| ∀ key, fs. key ∈ keys(fs, ax0) ↔ (∃ adr. adr ∈ ax0 ∧ fs[adr].key = key) ⊦ key ∈ keys(fs, ax0) ↔ (∃ adr0. adr0 ∈ ax0 ∧ fs[adr0].key = key), key = fs[adr].key |
key ∈ keys(fs, ax0), ∀ key, fs. key ∈ keys(fs, ax0) ↔ (∃ adr. adr ∈ ax0 ∧ fs[adr].key = key) ⊦ key ∈ keys(fs, ax0) ↔ (∃ adr0. adr0 ∈ ax0 ∧ fs[adr0].key = key), key = fs[adr].key
∀ key, fs. key ∈ keys(fs, ax0) ↔ (∃ adr. adr ∈ ax0 ∧ fs[adr].key = key) ⊦ key ∈ keys(fs, ax0) ↔ (∃ adr0. adr0 ∈ ax0 ∧ fs[adr0].key = key), key = fs[adr].key, key ∈ keys(fs, ax0)
Used formulas: key ∈ keys(fs, ax0)