tag:blogger.com,1999:blog-5240588941019541660.post7746552017254288244..comments2016-05-02T13:16:05.877-07:00Comments on Proof Theory Abridged: Independence of B\(\Sigma_2\) from I\(\Sigma_1\)Paulo Olivahttps://plus.google.com/109371735093431500627noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-5240588941019541660.post-53908619831312803692013-01-31T13:26:43.244-08:002013-01-31T13:26:43.244-08:00"One thing is to prove a certain statement A,..."One thing is to prove a certain statement <i>A</i>, another thing completely different is to prove that <i>A</i> is not provable!"<br /><br />I always heard that one cannot prove negative propositions! ;-)Jnoreply@blogger.com