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Proof step 2 from proof modnotreachable-reachable-rev-weak (previous step)

r0 ∈ H, reachable(r, r1, H[r0, ce]) ⊦ r0 = null, reachable(r, r1, H), reachable(r, r0, H)

User applied rule insert rewrite lemma

And obtained the following new goals

Proof step 3:
⊦ reachable(r, r0, H) ↔ (∃ x. path(r ' + x, H) ∧ (r ' + x).last = r0)
Proof step 4:
r0 ∈ H, ∃ x. path(r ' + x, H[r0, ce]) ∧ (r ' + x).last = r1 ⊦ r0 = null, reachable(r, r1, H), reachable(r, r0, H)

Rule argument

spec: inst: name: reachable-def seq: ⊦ reachable(r, r0, H) ↔ (∃ x. path(r ' + x, H) ∧ (r ' + x).last = r0) subst: [H, r0, r] → [H[r0, ce], r1, r] flags: rewrite, current

Additional information

Used terms: H[r0, ce], r1, r