Xor

As said before, an ordinary multiset can be viewed as a mapping that assigns a non-negative integer to each object, and which assigns the value zero to all but a finite number of objects (i.e. zero is the default value).

An inverted multiset can be viewed as a mapping that assigns a non-negative number, or the special value +infinity, and with +infinity as the default value. I.e. there are only a finite number of objects with a value less than +infinity. Note that *both* zero and +infinity can occur, so one can't just change the meaning of zero.

/ Niels Möller ()

Previous text:

2003-02-06 13:36: Subject: Xor

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Hm. Inverted sets. That would actually be useful, and not all that hard to implement either. :-)

/ Per Hedbor ()