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The predeclared functions succ, pred, and ord accept arguments of any ordinal type: 

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The relational operators =, <>, <, <=, >=, and> are applicable to all ordinal types provided both operands are ofthe same type. The order is determined by the values of the ordinal numbers underlying the operands. 

## 2.B The Type Boolean 

A Boolean value is one of the logical truth values denoted by the predefined identifiers false and true. 

These logical operators yield a Boolean value when applied to Boolean operands: (Appendix B summarizes all operators.) 

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Each of the relational operators (=, <>, <=, <, >, >=, in) yields a Boolean result. "<>" denotes inequality. Furthermore, the type Boolean is defined such that false < true. Hence, it is possible to define each of the 16 Boolean operations using the above logical and relational operators. For example, if p and Q are Boolean values, one can express 

