[R] stopifnot with logical(0)
maechler at stat.math.ethz.ch
Mon Dec 14 11:10:41 CET 2015
>>>>> "DM" == Duncan Murdoch <murdoch.duncan at gmail.com>
>>>>> on Sat, 12 Dec 2015 09:05:04 -0500 writes:
DM> On 12/12/2015 8:44 AM, peter dalgaard wrote:
>>> On 12 Dec 2015, at 10:54 , Martin Maechler
>>> <maechler at stat.math.ethz.ch> wrote:
>>> My conclusion: Breaking such a fundamental lemma of
>>> logic as "the empty set is always true"
>> Umm, that doesn't make sense to me. Surely you mean that
>> "an AND-operation over an empty index set is TRUE"? A
>> similar OR operation is FALSE, i.e. they behave like
>> empty products and sums, respectively.
DM> How about "the empty set is all true, and all false."
or, what the I *meant* with the above:
"All statements about elements of the empty set are true"
((and I still like the short form, even though it is not
correct strictly logically/mathematically))
Of course, Peter is correct, and that
any(logical(0)) is FALSE
is really the only sensical way.
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