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Polymorphism and Typing

Polymorhpic operations

• Take arguments from more than one semantic domain.
• Produced answer depends upon domains of arguments.
• Example: polymorphic addition on integers and rationals.

  (Integer × Integer) union (Rational × Rational) -> Integer union Rational

• Problem: dependence of codomain on domain is not explicitly stated.

Polymorphic operations do not fit cleanly into our semantic notation.