equal
deleted
inserted
replaced
3 *) |
3 *) |
4 |
4 |
5 section \<open>Peirce's Law\<close> |
5 section \<open>Peirce's Law\<close> |
6 |
6 |
7 theory Peirce |
7 theory Peirce |
8 imports Main |
8 imports Main |
9 begin |
9 begin |
10 |
10 |
11 text \<open> |
11 text \<open> |
12 We consider Peirce's Law: \<open>((A \<longrightarrow> B) \<longrightarrow> A) \<longrightarrow> A\<close>. This is an inherently |
12 We consider Peirce's Law: \<open>((A \<longrightarrow> B) \<longrightarrow> A) \<longrightarrow> A\<close>. This is an inherently |
13 non-intuitionistic statement, so its proof will certainly involve some form |
13 non-intuitionistic statement, so its proof will certainly involve some form |