Friday, 7 May 2004, 11:00 (note the unusual weekday and time!)
Cybernetica Bldg (Akadeemia tee 21), room B101
Abstract: In sequent calculus in natural deduction style, any multiplicities of active formulas can appear in the premisses of logical rules. No structural rules are needed, because multiplicity zero corresponds to weakening and greater than one to contraction.
Sequent calculus in natural deduction style is applied to simplify and complete Gentzen's third (1938) consistency proof of arithmetic.
S. Negri, J. von Plato. Sequent calculus in natural deduction style. J. of Symbolic Logic, v. 66, n. 4, pp. 1803-1816, 2001.