In recent years, peoples have studied many type systems, and the type systems with high order subtyping play an important role in the research of formal foundation of object oriented technology.

类型系统一直是理论计算机科学的研究热点，特别是带高阶子类型的多态类型系统的研究在探讨面向对象技术形式化理论基础中起着重要作用。

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In recent years, peoples have studied many type systems, and the type systems with high order subtyping play an important role in the research of formal foundation of object oriented technology.

类型系统一直是理论计算机科学的研究热点，特别是带高阶子类型的多态类型系统的研究在探讨面向对象技术形式化理论基础中起着重要作用。

youdao