feat: toNat_sub_of_le #5314
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feat: toNat_sub_of_le #5314
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This adds a simplification lemma for `(x - y).toNat` when the subtraction is known to not overflow (i.e., `y ≤ x`).
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This adds a simplification lemma for `(x - y).toNat` when the subtraction is known to not overflow (i.e., `y ≤ x`). We make a new section for this for two reasons: 1. Definitions of subtraction occur before the definition of `BitVec.le_def`, so we cannot directly place this lemma at `sub`. 2. There are other theorems of this kind, for addition and multiplication, which can morally live in the same section.
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This adds a simplification lemma for
(x - y).toNatwhen the subtraction is known to not overflow (i.e.,y ≤ x).We make a new section for this for two reasons:
BitVec.le_def, so we cannot directly place this lemma atsub.