| ⊦ mkDecimal(0, 0) ≤ dec_i ∧ mkDecimal(0, 0) ≤ dec_j → ¬ dec_i * dec_j < mkDecimal(0, 0) |
dec_i * dec_j < mkDecimal(0, 0), mkDecimal(0, 0) ≤ dec_i, mkDecimal(0, 0) ≤ dec_j, dec_i * dec_j < dec_i, dec_i * dec_j < dec_j ⊦
Used simplifier rules: ls-le-trans: ⊦ dec < dec0 ∧ dec0 ≤ dec1 → dec < dec1;