On Tuesday, 12 August 2014 at 09:17:54 UTC, Ola Fosheim Grøstad
wrote:
On Tuesday, 12 August 2014 at 08:07:01 UTC, Kagamin wrote:
A true reversal would be when preconditions are derived from
postconditions.
That's how you conduct a proof…
A proof usually flows from causes to consequences, the reverse
(induction) is ambiguous. Ordering is more fundamental: you can
define or redefine it, but it will remain, one can't think
outside of this formalism.
Not at all. You can create a boolean expression for every bit
of output and evaluate it only using NAND gates (or NOR). Not
practical, but doable…
Mathematics is pretty aware of differences between algorithms,
and proving their equivalence is non-trivial.
