I answered a StackOverflow question a while ago about why date ranges in Postgres are [x, y), or in other words include all t where x <= t < y: http://stackove

I answered a StackOverflow question a while ago about why date ranges in Postgres are [x, y), or in other words include all t where x <= t < y: http://stackoverflow.com/questions/37953786/why-does-postgres-upper-range-function-for-a-daterange-return-an-exclusive-boun http://stackoverflow.com/questions/37953786/why-does-postgre... It is interesting to see the same question applied to natural numbers, and Dijkstra landing on the same [x, y) recommendation. I'd say for natural numbers the argument is even stronger, since there is a least possible value.