我试图证明，在协议运行的跟踪中，消息不会是空的跟踪。最终的目标是证明没有主机会向自己发送消息。这似乎直观简单，所以我不确定发生了什么。我收到的错误是
Failed to apply initial proof method⌂:
using this:
[] ∈ ns_public
goal (1 subgoal):
1. ∀A B X. Says A B X ∉ set_of_list []
以下是相关代码。
inductive_set ns_public :: "event list set"
where
Nil[intro!,simp] : "[] ∈ ns_public" |
....
<snip>
....
lemma "∀ A B X. [] ∈ ns_public ⟶ Says A B X ∉ set_of_list []"
proof
assume "[] ∈ ns_public"
from this have "∀ A B X. Says A B X ∉ set_of_list []"
from this show "True" by blast
oops