Re: Generation of permutations

[Darren New <dnew@san.rr.com>]

tmoran@acm.org wrote:
> 
> > It's impossible to [always] reliably determine if a given set of instructions
> > (i.e., one given to you, not one chosen by you) does indeed sort an
> > arbitrary list of numbers.
>   With the word "always" that's true.  Without that word it's false.

If I give you a set of instructions, it's impossible for you to reliably
determine if that set of instructions implements a sort. "Reliably"
implies "always", doesn't it?  I mean, if I give you a block of
instructions and ask "does this implement a sort", and sometimes you can
say "Yes, I'm sure it does", and sometimes you can only say "I can't
tell", then doesn't that mean your program doesn't reliably give the
right answer? Again, we're talking about the method of figuring out
whether it's a sort that's reliable, not whether the program itself
sorts correctly. Your program doesn't reliably calculate square roots if
it only works for the number 25 either - it has to work for all inputs
in the domain.

I mean, my car starts very reliably, except when it doesn't.  That
doesn't make any sense.

-- 
Darren New 
San Diego, CA, USA (PST). Cryptokeys on demand.
   The 90/10 rule of toothpaste: the last 10% of 
         the tube lasts as long as the first 90%.