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New reals: Can live with them, can live without them

Martin Goldstern·Jakob Kellner
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Abstract

We give a self-contained proof of the preservation theorem for proper countable support iterations known as "tools-preservation," "Case A" or "first preservation theorem" in the literature. We do not assume that the forcings add reals.

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Martin Goldstern, Jakob Kellner. 2005-05-23. New reals: Can live with them, can live without them. https://doi.org/10.1002/malq.200510018

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