[FOM] Disjunction: in or ex?

[Martin Davis]

Two remarks that no one yet has made on this thread:

Historical: Boole only permitted union of two sets when they are 
disjoint, so the distinction didn't arise.

Legal: In contracts in the US, I have seen "and/or" used to indicate 
inclusive disjunction.

Martin


                           Martin Davis
                    Visiting Scholar UC Berkeley
                      Professor Emeritus, NYU
                          martin at eipye.com
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