This paper provides a detailed comparison between discourse representation theory (DRT) and dependent type semantics (DTS), two frameworks for discourse semantics. Although it is often stated that DRT and those frameworks based on dependent types are mutually exchangeable, we argue that they differ with respect to variable handling, more specifically, how substitution and other operations on variables are defined. This manifests itself in two recalcitrant problems posed for DRT; namely, the overwrite problem and the duplication problem. We will see that these problems still pose a challenge for various extended compositional systems based on DRT, while they do not arise in a framework of DTS where substitution and other operations are defined in the standard type-theoretic manner without stipulating any additional constraints. We also compare the notions of contexts underlying these two kinds of frameworks, namely, contexts represented as assignment functions and contexts represented as proof terms, and see what different predictions they make for some linguistic examples.

中文翻译：

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变量处理和组合性：比较 DRT 和 DTS

本文提供了话语表示理论（DRT）和依赖类型语义（DTS）这两种话语语义框架之间的详细比较。虽然经常说 DRT 和那些基于依赖类型的框架是可以相互交换的，但我们认为它们在变量处理方面有所不同，更具体地说，是如何定义变量的替换和其他操作。这体现在 DRT 提出的两个顽固问题上；即覆盖问题和重复问题。我们将看到，这些问题仍然对基于 DRT 的各种扩展组合系统构成挑战，而它们不会出现在 DTS 框架中，在 DTS 框架中，替换和其他操作以标准类型理论的方式定义，而没有规定任何额外的约束。