331–332 of 332 posts
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While true, that's too strict. An Abelian group (like any group) needs inverses. You get distributed computation if you've got an Abelian semigroup.
To be fair, Abel did not know (or care) about semigroups.
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Databases have support for a single type that encodes exactly like this. In postgresql a timestamptz shows as 'yyyy-mm-dd hh:mm:ss.123456+1234' but internally it's stored as UTC unixtime and tz offset.
Doesn't it actually store the timezone's IANA name and uses the tzdata to do conversions? That implies slightly more work than storing just the effective timezone offset, but is probably more correct when it comes to the timestamps in the future.