Seminars

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ABSTRACT: A metric space $M$ is called Expand-Contract plastic (or just plastic) if every non-expansive bijection $F\colon M\to M$ is an isometry. An intriguing open question is whether the closed unit ball of every Banach space is plastic as a metric space with the metric generated by the norm. There are only several particular results in this direction. The talk will be concentrated on these results, and also on some natural generalizations of plactisity problem and related questions.