Fwd: [TYPES] Article on proof theory of type theory
cpratt-UYko1UTVIqz2fBVCVOL8/[email protected]
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----- Forwarded message from Anton Setzer <a.g.setzer-QvkbJbr/[email protected]> ----- Date: Sun, 29 Feb 2004 17:10:10 +0000 From: Anton Setzer <a.g.setzer-QvkbJbr/[email protected]> Reply-To: Anton Setzer <a.g.setzer-QvkbJbr/[email protected]> Subject: [TYPES] Article on proof theory of type theory To: [email protected] [The Types Forum, http://lists.seas.upenn.edu/mailman/listinfo/types-list] Dear all, I have written an overview article over type theory of Martin-L"of type theory. It is intended for the reader who doesn't know much about proof theory but has some knowledge about type theory. I hope it is easy to read. It is available via http://www.cs.swan.ac.uk/~csetzer/articles/overviewProofTheoryTypeTheory2004.pdf (Versions in .dvi, .ps, .bib format are as well available by exchanging .pdf by these extensions) Related articles are available from my homepage, http://www.cs.swan.ac.uk/~csetzer Anton Setzer Abstract ~~~~~~~~ We give an overview over the historic development of proof theory and the main techniques used in ordinal theoretic proof theory. We argue, that in a revised Hilbert's programme, ordinal theoretic proof theory has to be supplemented by a second step, namely the development of strong equiconsistent constructive theories. Then we show, how, as part of such a programme, the proof theoretic analysis of Martin-L"of type theory with $\Wrm$-type and one microscopic universe containing only two finite sets is carried out. Then we look at the analysis of Martin-L"of type theory with $\Wrm$-type and a universe closed under the $\Wrm$-type, and consider the extension of type theory by one Mahlo universe and its proof-theoretic analysis. Finally we repeat the concept of inductive-recursive definitions, which extends the notion of inductive definitions substantially. We introduce a closed formalisation, which can be used in generic programming, and explain, what is known about its strength. Keywords: Martin-L"of type theory, proof theory, Kripke-Platek set theory, $\Wrm$-type, well-founded trees, Kleene's O, Mahlo universe, inductive-recursive definitions, generic programming. ----------------------------------------------------------------------------- Anton Setzer Telephone: Department of Computer Science (national) (01792) 513368 University of Wales Swansea (international) +44 1792 513368 Singleton Park Fax: Swansea SA2 8PP (national) (01792) 295708 UK (international) +44 1792 295708 Visiting address: Email: [email protected] Faraday Building, WWW: Computer Science Dept. http://www.cs.swan.ac.uk/~csetzer/ 2nd floor, room 211. ------------------------------------------------------------------------------ ----- End forwarded message -----