Surprising behaviour of Set

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Jun 25, 2017, 1:10:31 PM6/25/17

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I just noticed that Set([[], []]).cardinality() yields 2. In earlier versions, a TypeError: unhashable type: 'list' was raised.

I think the behaviour was modified in https://trac.sagemath.org/ticket/22597.

Is this intended? It seems to me that it would be safer if cardinality would raise an error...

Martin

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Jun 25, 2017, 1:41:15 PM6/25/17

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a set theorist would be very happy :)

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Jun 25, 2017, 1:47:36 PM6/25/17

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I hope it was not intentional. It looks seriously broken. Did you
already opened a ticket?

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Jun 25, 2017, 3:05:05 PM6/25/17

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