Separating dag-like and tree-like proof systems
P Nguyen - 22nd Annual IEEE Symposium on Logic in …, 2007 - ieeexplore.ieee.org
We show that tree-like (Gentzen's calculus) PK where all cut formulas have depth at most a
constant d does not simulate cut-free PK. Generally, we exhibit a family of sequents that …
constant d does not simulate cut-free PK. Generally, we exhibit a family of sequents that …