论文标题
连续和单调机器
Continuous and monotone machines
论文作者
论文摘要
我们研究了基于燃料的方法的变体,用于建模类型理论的分歧计算,并用它抽象地捕获Oracle Turing机器的本质。我们称之为连续机器的结果对象。我们证明,可以在可计算分析中使用的标准函数中在此类机器和名称之间来回翻译。换句话说,在Baire空间上的运算符中,完全连续的机器可通过连续机器实现,并且该机器提供的数据是对操作员的描述,将操作员描述为可依次可实现的功能。 连续机器在类型理论中是自然配制的,我们已经在COQ中正式化了我们的发现。连续机器,它们与基本操作的标准编码和正确性的等效性现在是Incone的一部分,Incone是可计算分析的COQ库。虽然正确性证明使用具有可计数选择的经典元理论,但被证明正确的翻译和算法都是完全可执行的。在途中,我们正式证明了一些已知的结果,例如在Baire空间上部分连续操作员的连续性模量存在。 为了说明它们的多功能性,我们使用连续的机器来指定一些无法通过有限态度(例如实数和功能)完全描述的对象操作的算法。我们提出了特别简单的算法,用于查找实际数字的乘法倒数以及在Baire空间上部分连续算子组成。通过利用连续机器与多价语义兼容的事实,可以实现一些简单性。我们还将连续的机器连接到预先完成的构建和代表空间的完成,这些主题最近引起了可计算分析社区的关注。
We investigate a variant of the fuel-based approach to modeling diverging computation in type theories and use it to abstractly capture the essence of oracle Turing machines. The resulting objects we call continuous machines. We prove that it is possible to translate back and forth between such machines and names in the standard function encoding used in computable analysis. Put differently, among the operators on Baire space, exactly the partial continuous ones are implementable by continuous machines and the data that such a machine provides is a description of the operator as a sequentially realizable functional. Continuous machines are naturally formulated in type theories and we have formalized our findings in Coq. Continuous machines, their equivalence to the standard encoding and correctness of basic operations are now part of Incone, a Coq library for computable analysis. While the correctness proofs use a classical meta-theory with countable choice, the translations and algorithms that are proven correct are all fully executable. Along the way we formally prove some known results such as existence of a self-modulating moduli of continuity for partial continuous operators on Baire space. To illustrate their versatility we use continuous machines to specify some algorithms that operate on objects that cannot be fully described by finite means, such as real numbers and functions. We present particularly simple algorithms for finding the multiplicative inverse of a real number and for composition of partial continuous operators on Baire space. Some of the simplicity is achieved by utilizing the fact that continuous machines are compatible with multivalued semantics. We also connect continuous machines to the construction of precompletions and completions of represented spaces, topics that have recently caught the attention of the computable analysis community.