Current GEP research lacks theoretical foundation. This baffles the developing of GEP. To remedy this issue, this study, defined schema and relative concepts over GEP, analyzed the mechanisms for operators in GEP via probability method, gave proof for the schema theorem over GEP, validated theoretical results by extensive experiments and demonstrates the practical application of schema theorem over GEP. The schema theorem proposed in this paper provides quantitative standard for GEP algorithm’s improving.
