# Blog Archives

# Topic Archive: Borel Conjecture

Set theory seminarFriday, April 4, 201410:00 amGC6417

# On the independence of Borel’s Conjecture

The CUNY Graduate Center

In 1919 Borel introduced the notion of a strong measure zero set and stated what has become known as Borel’s conjecture (BC): every strong measure zero set of reals is countable. SierpiĆski soon proved (1928) that CH implies the failure of BC. However, a proof for the consistency of BC with ZFC would have to wait for the development of more powerful tools. In 1976, Laver used an iterated forcing argument to produce a model of ZFC + BC. I will present an exposition of these classical results. Time permitting, I will sketch some analogous results for the dual Borel Conjecture, the category analogue of BC.