[STATEMENT]
lemma triangle_set_power_set_ss: "triangle_set \<subseteq> Pow V"
[PROOF STATE]
proof (prove)
goal (1 subgoal):
 1. triangle_set \<subseteq> Pow V
[PROOF STEP]
by (auto simp add: triangle_set_def triangle_in_graph_def wellformed_alt_fst wellformed_alt_snd)