Leo Harrington showed that the second-order theory of arithmetic WKL0 is 1 1-conservative over the theory RCA0. Harrington's proof is model-theoretic, making use of a forcing...
This paper defines the cover of a formula with respect to a set of variables V in theory T to be the strongest quantifier-free formula that is implied by V : in theory T. Cover e...
: Interval arithmetic was introduced by Ramon Moore [Moo66] in the 1960s as an approach to bound rounding errors in mathematical computation. The theory of interval analysis emerge...
Younis Hijazi, Hans Hagen, Charles D. Hansen, Kenn...
Abstract. We present a formally verified quantifier elimination procedure for the first order theory over linear mixed real-integer arithmetics in higher-order logic based on a wor...
First order reasoning about hyperintegers can prove things about sets of integers. In the author's paper Nonstandard Arithmetic and Reverse Mathematics, Bulletin of Symbolic L...