src/ZF/ex/NatSum.thy
2011-02-18 wenzelm 2011-02-18 more precise headers;
2010-03-13 wenzelm 2010-03-13 removed old CVS Ids; tuned headers;
2005-06-17 haftmann 2005-06-17 migrated theory headers to new format
2002-02-04 paulson 2002-02-04 New-style versions of these old examples
2000-08-18 paulson 2000-08-18 new example ZF/ex/NatSum