On the extension property of measurable spaces
On the extension property of measurable spaces
We prove that a metrizable measurable space has the extension property if and only if it is isomorphic to a Borel subset of the real line. It follows, in particular, that <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis bold upper R comma script upper P left-parenthesis bold upper R right-parenthesis right-parenthesis"> <mml:semantics> …