2355 size. Moreover, our result is a good |
2355 size. Moreover, our result is a good |
2356 witness for one of the major reasons to be interested in machine checked |
2356 witness for one of the major reasons to be interested in machine checked |
2357 reasoning: gaining deeper understanding of the subject matter. |
2357 reasoning: gaining deeper understanding of the subject matter. |
2358 |
2358 |
2359 Our formalisation |
2359 Our formalisation |
2360 consists of around 600 lemmas and overall 10800 lines |
2360 consists of around 600 lemmas and overall 9200 lines |
2361 of readable and commented Isabelle/Isar |
2361 of readable and commented Isabelle/Isar |
2362 code with a few apply-scripts interspersed. The formal model of PIP |
2362 code with a few apply-scripts interspersed. The formal model of PIP |
2363 is 620 lines long; our graph theory implementation using relations is |
2363 is 310 lines long; our graph theory implementation using relations is |
2364 1860 lines; the basic properties of PIP take around 5500 lines of code; |
2364 1615 lines; the basic properties of PIP take around 5000 lines of code; |
2365 and the formal correctness proof 1700 lines. |
2365 and the formal correctness proof 1250 lines. |
2366 %Some auxiliary |
2366 %Some auxiliary |
2367 %definitions and proofs span over 770 lines of code. |
2367 %definitions and proofs span over 770 lines of code. |
2368 The properties relevant |
2368 The properties relevant |
2369 for an implementation require 1000 lines. |
2369 for an implementation require 1000 lines. |
2370 The code of our formalisation |
2370 The code of our formalisation |
2371 can be downloaded from the Mercurial repository at |
2371 can be downloaded from the Mercurial repository at |
2372 \url{http://www.dcs.kcl.ac.uk/staff/urbanc/cgi-bin/repos.cgi/pip}. |
2372 \url{http://talisker.inf.kcl.ac.uk/cgi-bin/repos.cgi/pip}. |
2373 |
2373 |
2374 %\medskip |
2374 %\medskip |
2375 |
2375 |
2376 %\noindent |
2376 %\noindent |
2377 %{\bf Acknowledgements:} |
2377 %{\bf Acknowledgements:} |