Editing Structured program theorem (section)

=== Böhm and Jacopini's proof ===
{{expand section|date=July 2014}}
The proof in Böhm and Jacopini's paper proceeds by [[structural induction|induction on the structure]] of the flow chart.<ref name="Harel"/>{{rp|381}} Because it employed [[Subgraph isomorphism problem|pattern matching in graphs]], the proof of Böhm and Jacopini's was not really practical as a [[program transformation]] algorithm, and thus opened the door for additional research in this direction.<ref name="amma92"/>