Abstract: We will concentrate on two papers by Marina Ratner: "Horocycle flows are loosely Bernoulli". Israel J. Math. 31 (1978) no. 2, 122-132. and "The Cartesian square of the horocycle flow is not loosely Bernoulli". Israel J. Math. 34 (1979). , no. 1-2, 72-96 (1980). We will start from the definition of loosely Bernoulli, then a detailed discussion about the proof that horocycle flow is loosely Bernoulli and finally some hints about the non-loosely Bernoulli proof in the product case.

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