Date of Original Version

1996

Type

Article

Rights Management

All Rights Reserved

Abstract or Description

We show that certain model-theoretic forcing arguments involving subsystems of second-order arithmetic can be formalized in the base theory, thereby converting them to effective proof-theoretic arguments. We use this method to sharpen the conservation theorems of Harrington and Brown-Simpson, giving an effective proof that WKL+0 is conservative over RCA0 with no significant increase in the lengths of proofs.

DOI

10.1016/0168-0072(96)00003-6

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Philosophy Commons

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