Operator Precedence/Boolean Logic

[Chris Angelico]

On Thu, Jun 23, 2016 at 7:23 PM, Antoon Pardon
<antoon.pardon at rece.vub.ac.be> wrote:
> I don't care. In modern mathematics, zero is usaly defined as the
> empty set. The empty set contains nothing, but it isn't nothing
> itself. Otherwise the empty set would be the same as the set
> containing the empty set, since they both would contain the same,
> being nothing.

Zero is *the cardinality of* the empty set. The set containing the
empty set has a cardinality of 1.

ChrisA