Ltac start_unchanged :=
    red; intros; eapply one_leaderLog_per_term_unchanged; eauto; subst.(* solve invariant by lemma which shows leader logs do not change *)
  Ltac unchanged lem :=
    start_unchanged; apply lem.

Lemma contradiction_case : forall (net : network ) t ll ll' (h h' : name) (p : packet (params := refined_multi_params (multi_params := multi_params))) t0 v xs ys, refined_raft_intermediate_reachable net -> pBody p = RequestVoteReply (raft_params := raft_params) t0 v -> nwPackets net = xs ++ p :: ys -> In (t, ll) (leaderLogs (fst (nwState net h))) -> In (t, ll') (leaderLogs (update_elections_data_requestVoteReply (pDst p) (pSrc p) t0 v (nwState net (pDst p)))) -> pDst p = h' -> pDst p <> h -> False.