fact: Definition oppℝ_Req_proper := λ"eq" λ"ε₁" λ"ε₂" λ"q₁" λ"q₂" λ"X" λ"Y" ℚopp @ "q₂" @ (ℚopp @ "q₁" @ ("eq" @ "ε₁" @ "ε₂")) @ "X" @ "Y".
imports: QArith Psatz ClassicalRealizability.Kbase ClassicalRealizability.Rationals ClassicalRealizability.Real_definitions ClassicalRealizability.Real_relations