gcd 0 0 = 0

[Marc van Dongen]

Lars Henrik Mathiesen (thorinn@diku.dk) wrote:

: > Alan Bawden (Alan@LCS.MIT.EDU) wrote:
: > : Indeed, that's a nice way of putting it.  How about if the report just
: > : says:
: > : 
: > :    In order to make the non-negative integers into a lattice under `gcd'
: > :    and `lcm', we define `gcd 0 0 = 0'.

[snip]

: This is exactly what you get if you plug the relation 'divides' on the
: non-negative integers into the definition of meet in a lattice. So
: this formulation is no more or less complex to use than the lattice
: one --- and people who do know about lattices will probably realize
: this pretty fast.

I disagree. Alan is talking about adding things to the haskell report.
That document should be accessible to as many people as possible.
I have not yet met anybody who had lattice theory in primary and/or
secondary school. On the other hand I *have* met quite a few of them
who have a pretty good idea about what it means for one number to
divide another.

[snip]

Regards,


Marc van Dongen
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