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Field-arithmetic-operations

Op-field-sub

Leo field subtraction operation.

Signature
(op-field-sub left right curve) → result
Arguments: left — Guard (valuep left).; right — Guard (valuep right).; curve — Guard (curvep curve).
Returns: result — Type (value-resultp result).

Definitions and Theorems

Function: op-field-sub

(defun op-field-sub (left right curve)
  (declare (xargs :guard (and (valuep left)
                              (valuep right)
                              (curvep curve))))
  (declare (xargs :guard (and (value-case left :field)
                              (value-case right :field))))
  (let ((__function__ 'op-field-sub))
    (declare (ignorable __function__))
    (b* ((err (list :op-field-sub (value-fix left)
                    (value-fix right)))
         (p (curve-base-prime curve))
         (x (value-field->get left))
         (y (value-field->get right))
         ((unless (pfield::fep x p))
          (reserrf err))
         ((unless (pfield::fep y p))
          (reserrf err)))
      (value-field (pfield::sub x y p)))))

Theorem: value-resultp-of-op-field-sub

(defthm value-resultp-of-op-field-sub
  (b* ((result (op-field-sub left right curve)))
    (value-resultp result))
  :rule-classes :rewrite)

Theorem: op-field-sub-of-value-fix-left

(defthm op-field-sub-of-value-fix-left
  (equal (op-field-sub (value-fix left)
                       right curve)
         (op-field-sub left right curve)))

Theorem: op-field-sub-value-equiv-congruence-on-left

(defthm op-field-sub-value-equiv-congruence-on-left
  (implies (value-equiv left left-equiv)
           (equal (op-field-sub left right curve)
                  (op-field-sub left-equiv right curve)))
  :rule-classes :congruence)

Theorem: op-field-sub-of-value-fix-right

(defthm op-field-sub-of-value-fix-right
  (equal (op-field-sub left (value-fix right)
                       curve)
         (op-field-sub left right curve)))

Theorem: op-field-sub-value-equiv-congruence-on-right

(defthm op-field-sub-value-equiv-congruence-on-right
  (implies (value-equiv right right-equiv)
           (equal (op-field-sub left right curve)
                  (op-field-sub left right-equiv curve)))
  :rule-classes :congruence)

Theorem: op-field-sub-of-curve-fix-curve

(defthm op-field-sub-of-curve-fix-curve
  (equal (op-field-sub left right (curve-fix curve))
         (op-field-sub left right curve)))

Theorem: op-field-sub-curve-equiv-congruence-on-curve

(defthm op-field-sub-curve-equiv-congruence-on-curve
  (implies (curve-equiv curve curve-equiv)
           (equal (op-field-sub left right curve)
                  (op-field-sub left right curve-equiv)))
  :rule-classes :congruence)