fact: Definition D := λ"l" λ"r" callcc @ λ"k" "l" @ λ"qx" λ"qx'" λ"x" callcc @ λ"k'" "k" @ ("r" @ λ"qy" λ"qy'" λ"y" ℚle @ "qy" @ "qx'" @ "x" @ ("k'" @ "y")).
imports: QArith Psatz ClassicalRealizability.Kbase ClassicalRealizability.Rationals