fact: Definition oppℝ_addℝ := λ"Cx" λ"ε" λ"ε₀" λ"q" λ"q₀" λ"X+(-X)" λ"0" "0" @ "X+(-X)" @ (λ"ε₁" λ"ε₂" λ"q₁" λ"q₂" ℚopp @ "q₂" @ ("Cx" @ "ε₁" @ "ε₂" @ "q₁")).
imports: QArith Psatz ClassicalRealizability.Kbase ClassicalRealizability.Rationals ClassicalRealizability.Real_definitions ClassicalRealizability.Real_relations