| # ax1 = # ax0, adr ∈ ri, ax1.toSet ⊆ range ri, ∀ key. key ∈ ri → ri[key] ∈ fs ∧ key-cons(key, fs[ri[key]]) ⊦ fs[adr].key ∈ keys(fs, ax1), fs[adr].key ∈ ri |
⊦ adr ∈ ri ↔ (∃ key. key ∈ ri ∧ ri[key] = adr)
# ax1 = # ax0, ax1.toSet ⊆ range ri, ∀ key. key ∈ ri → ri[key] ∈ fs ∧ key-cons(key, fs[ri[key]]), ∃ key. key ∈ ri ∧ ri[key] = adr ⊦ fs[adr].key ∈ ri, fs[adr].key ∈ keys(fs, ax1)
Used terms: ri, adr