Practical Foundations of Mathematics
Practical Foundations of Mathematics
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DOI:
10.5860/choice.37-4551
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发表时间:
1999
期刊:
影响因子:
--
通讯作者:
P. Taylor
中科院分区:
文献类型:
--
作者:
P. Taylor
The book presents a very well-chosen selection of mathematical notions and techniques as they are relevant for the foundations of Mathematics and Computer Science. The somewhat mysterious word “practical” in the title simply insinuates that the author doesn’t want “foundations” to be understood in any “foundational” sense. The aim rather is to exhibit and study the mathematical principles behind logic and induction as needed and used for the formalisation of (the main parts of) Mathematics and Computer Science. However, instead of classical logic and set theory, the book is based on and provides an introduction to constructive logic and type theory, the latter being much closer to mathematical practice than set theory. Constructive logic is also discussed from the point of view of propositions-as-types where proofs appear as sort of functional programs thus bridging the gap between logic and computation. The mathematical structures employed for providing a mathematical underpinning are mainly categorical in nature thus allowing for general and concise formulations. Whereas till the last chapter the underlying logic is intuitionistic higher-order logic ( a la Church, i.e. based on functions and a type of propositions) in the nal chapter one nds a thorough discussion of the set-theoretic axiom of Replacement and strong arguments in favour of type-theoretic universes as capturing the essence of the axiom of Replacement in a type theoretic framework. As opposed to most texts on constructive type theory which are very syntactically inclined in the current book the use of type-theoretic language is much more informal which is in accordance with the informal way set theory is used in mathematics. Next, we survey the contents of the book in more detail. The rst chapter introduces the basics of First-Order Reasoning with an emphasis on a box calculus providing a graphical visualisation of the handling of contexts in natural deduction. The second chapter on Types and Induction discusses sum, product and function types, the paradigm of propositions-as-types and the technique of structural induction exempli ed by natural numbers and lists.