[FOM] Use of ex falso quodlibet (EFQ)

Arnon Avron aa at tau.ac.il
Mon Aug 31 04:49:41 EDT 2015

On Mon, Aug 31, 2015 at 02:20:33AM +0000, Tennant, Neil wrote:

> In Core Logic, *there is no rule of EFQ*. That's because mathematicians NEVER (NEED TO) USE IT!

I have always thought that  mathematicians (NEED TO) USE  it, e.g.,
when they claim that the empty set is a subset of any other set.
Do you have another logical explanation of this claim
on the basis of the standard definitions of the empty set
and the subset relation?


Arnon Avron

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