[STATEMENT]
lemma trss_stack_comp_s: 
  "((s,c),e,(s',c'))\<in>trss fg \<Longrightarrow> ((s@r,c),e,(s'@r,c'))\<in>trss fg"
[PROOF STATE]
proof (prove)
goal (1 subgoal):
 1. ((s, c), e, s', c') \<in> trss fg \<Longrightarrow> ((s @ r, c), e, s' @ r, c') \<in> trss fg
[PROOF STEP]
by (auto elim!: trss.cases intro: trss.intros)