(subclass NonnegativeInteger Integer) | Merge.kif 1975-1975 | 子類 NonnegativeInteger and Integer |
(subclass NonnegativeInteger NonnegativeRealNumber) | Merge.kif 1976-1976 | 子類 NonnegativeInteger and NonnegativeRealNumber |
(subclass PositiveInteger NonnegativeInteger) | Merge.kif 1994-1994 | 子類 PositiveInteger and NonnegativeInteger |