simplified/refined document model: collection of named nodes, without proper dependencies yet;
moved basic type definitions for ids and edits from Isar_Document to Document;
removed begin_document/end_document for now -- nodes emerge via edits;
edits refer to named nodes explicitly;
lemma app_Nil2 [simp]: "xs @ [] = xs"
apply(induct_tac xs)
apply(auto)
done
lemma app_assoc [simp]: "(xs @ ys) @ zs = xs @ (ys @ zs)"
apply(induct_tac xs)
apply(auto)
done
lemma rev_app [simp]: "rev(xs @ ys) = (rev ys) @ (rev xs)"
apply(induct_tac xs)
apply(auto)
done
theorem rev_rev [simp]: "rev(rev xs) = xs"
apply(induct_tac xs)
apply(auto)
done
end