| st[r0 -- _type] .type ≤ ty, is_obj(str, r0, st), ∀ str, ty, st, r, sk, val. (validrefs(str, acc, ty, st[r -- sk, val]) ↔ validrefs(str, acc, ty, st)) ∨ r ∈ acc ⊦ validrefs(str, r0 ' + acc, ty, st[r -- sk, val]) ↔ acc = [] ∨ (∃ fs. fs ' ∈ instfields(st[r0 -- _type] .type .class) ∧ is_referencevalue(st[r0 -- fs ']) ∧ acc .first = st[r0 -- fs '] .refval ∧ validrefs(str, acc, fs .type, st)), r = r0, r0 = jvmref, r ∈ acc |
⊦ is_obj(str, r, st) ∧ st[r -- _type] .type ≤ ty → ( validrefs(str, r ' + refs, ty, st) ↔ refs = [] ∨ (∃ fs. fs ' ∈ instfields(st[r -- _type] .type .class) ∧ is_referencevalue(st[r -- fs ']) ∧ refs .first = st[r -- fs '] .refval ∧ validrefs(str, refs, fs .type, st)))
is_obj(str, r0, st[r -- sk, val]) ∧ (st[r -- sk, val][r0 -- _type]) .type ≤ ty, st[r0 -- _type] .type ≤ ty, is_obj(str, r0, st), ∀ str, ty, st, r, sk, val. (validrefs(str, acc, ty, st[r -- sk, val]) ↔ validrefs(str, acc, ty, st)) ∨ r ∈ acc ⊦ acc = [] ∨ (∃ fs. fs ' ∈ instfields((st[r -- sk, val][r0 -- _type]) .type .class) ∧ is_referencevalue(st[r -- sk, val][r0 -- fs ']) ∧ acc .first = (st[r -- sk, val][r0 -- fs ']) .refval ∧ validrefs(str, acc, fs .type, st[r -- sk, val])) ↔ acc = [] ∨ (∃ fs. fs ' ∈ instfields(st[r0 -- _type] .type .class) ∧ is_referencevalue(st[r0 -- fs ']) ∧ acc .first = st[r0 -- fs '] .refval ∧ validrefs(str, acc, fs .type, st)), r = r0, r0 = jvmref, r ∈ acc
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ r ≠ r0 → ( is_obj (str, r0, st[r -- sk, val]) ↔ is_obj(str, r0, st))], [CSIMPSEQ : ⊦ r ≠ r0 → (st[r0 -- sk0, val][r -- sk]) = st[r -- sk]])], [EXTRATERMS : (st[r -- sk, val], ty, acc, r0, str)]]