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    Normalize-<-minus-/

    Rewrite inequalities between 0 and negated or reciprocal terms, and (< (- x) (- y)).

    Definitions and Theorems

    Theorem: normalize-<-minus-/

    (defthm normalize-<-minus-/
            (and (equal (< (- x) 0) (< 0 x))
                 (equal (< 0 (- x)) (< x 0))
                 (equal (< (- x) (- y)) (> x y))
                 (implies (real/rationalp x)
                          (and (equal (< 0 (/ x)) (< 0 x))
                               (equal (< (/ x) 0) (< x 0))))))