“School of Mathematics”

Back to Papers Home
Back to Papers of School of Mathematics

Paper   IPM / M / 15444
School of Mathematics
  Title:   On constructivity and the Rosser property: a closer look at some Godelean proofs
  Author(s):  Saeed Salehi (Joint with P. Seraji)
  Status:   Published
  Journal: Ann. Pure Appl. Logic
  Vol.:  169
  Year:  2018
  Pages:   971-980
  Supported by:  IPM
  Abstract:
The proofs of Kleene, Chaitin and Boolos for Gödel's First Incompleteness Theorem are studied from the perspectives of constructivity and the Rosser property. A proof of the incompleteness theorem has the Rosser property when the independence of the true but unprovable sentence can be shown by assuming only the (simple) consistency of the theory. It is known that Gödel's own proof for his incompleteness theorem does not have the Rosser property, and we show that neither do Kleene's or Boolos' proofs. However, we show that a variant of Chaitin's proof can have the Rosser property. The proofs of Gödel, Rosser and Kleene are constructive in the sense that they explicitly construct, by algorithmic ways, the independent sentence(s) from the theory. We show that the proofs of Chaitin and Boolos are not constructive, and they prove only the mere existence of the independent sentences.

Download TeX format
back to top
scroll left or right