In an appendix to his book on mathematical existence , Becker set the problem of finding a formal calculus for intuitionistic logic .
Becker failed in the end to correctly distinguish classical and intuitionistic negation , but he made a start .
In an appendix to Becker 's book on mathematical existence , Becker set the problem of finding a formal calculus for intuitionistic logic .
Becker failed in the end to correctly distinguish classical and intuitionistic negation , but he made a start .