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# On Nonisomorphic Analytic Sets

R. Daniel Mauldin
Proceedings of the American Mathematical Society
Vol. 58, No. 1 (Jul., 1976), pp. 241-244
DOI: 10.2307/2041393
Stable URL: http://www.jstor.org/stable/2041393
Page Count: 4
It is shown that if $A$ is an analytic subset of $I$, the unit interval, such that $I - A$ is uncountable and does not contain a perfect set, then $A$ is not Borel isomorphic to $I \times A$ or to $A^n, n > 1$, or to $U$, where $U$ is a universal analytic subset of $I^2$. It is also shown that $U$ is not isomorphic to $I \times A$ or to $A^n, n > 1$.