is mentioned by

Thm* For any graph the_obj:GraphObject(the_graph), L:V List, s:Traversal, x:V. dfl-traversal(the_graph;L;s) (j:V. (inr(j) s) (inl(j) s) j-the_graph- > *x) dfl-traversal(the_graph;L @ [x];dfs(the_obj;s;x))	[dfs-dfl-traversal]
Thm* For any graph the_obj:GraphObject(the_graph), s:Traversal, i:V. df-traversal(the_graph;s) (j:V. (inr(j) s) (inl(j) s) j-the_graph- > *i) df-traversal(the_graph;dfs(the_obj;s;i))	[dfs-df-traversal]
Thm* For any graph the_obj:GraphObject(the_graph), P:(VTraversalTraversalProp), s:Traversal, i:V. (s:Traversal, i:V. (inl(i) s) (inr(i) s) P(i,s,nil)) (s1,s2,s3:Traversal, i,j:V. i-the_graph- > j paren(V;s2) (k:V. (inr(k) s2) j-the_graph- > *k) paren(V;s3) P(j,s1,s2) P(i,s2 @ s1,s3) P(i,s1,s3 @ s2)) (s1,s2:Traversal, i:V. (inr(i) s1) (inl(i) s1) paren(V;s2) l_disjoint(V+V;s2;s1) no_repeats(V+V;s2) (j:V. (inr(j) s2) i-the_graph- > *j) (j:V. i-the_graph- > j j = i (inl(j) s2) (inl(j) s1) (inr(j) s1)) P(i,[inr(i) / s1],s2) P(i,s1,[inl(i) / (s2 @ [inr(i)])])) (s':Traversal. P(i,s,s') & l_disjoint(V+V;s';s) & no_repeats(V+V;s') & paren(V;s') & (j:V. (inr(j) s') i-the_graph- > *j) & dfs(the_obj;s;i) = (s' @ s))	[dfs_induction4]
Thm* For any graph the_obj:GraphObject(the_graph), s:Traversal, i:V. s':Traversal. ((inr(i) s) (inl(i) s) s' = nil) & ((inr(i) s) & (inl(i) s) (s2:Traversal. s' = ([inl(i)] @ s2 @ [inr(i)]) Traversal)) & l_disjoint(V+V;s';s) & no_repeats(V+V;s') & paren(V;s') & (j:V. (inr(j) s') i-the_graph- > *j) & dfs(the_obj;s;i) = (s' @ s)	[dfs-properties]
Thm* For any graph the_obj:GraphObject(the_graph), s:Traversal, i:V. s':Traversal. (j:V. (inr(j) s') i-the_graph- > *j) & dfs(the_obj;s;i) = (s' @ s)	[dfs-connect]

In prior sections: graph 1 2

Try larger context: Graphs