Re: [boost] Formal Review for Interval Library beginning

From: Joel Young (jdy_at_[hidden])
Date: 2002-09-03 17:39:48

From: Herve Bronnimann <hbr_at_[hidden]>
> What this means is that there is no hope of defining operator< in a way

Right.

Assuming durationless intervals are disallowed there are thirteen
mutually exclusive interval-interval relations:

six (precedes, meets, during, starts, finishes, overlaps), their mirrors, plus equals.

< is used to denote precedes.  <= is the disjunction of precedes and
equals which does not include meets, starts, or overlaps.

Here is an old diagram:
http://www.cs.indiana.edu/event/maics96/Proceedings/Young/img3.gif

Let A be the disjunctive set of all thirteen interval relations (just as
<= denotes the disjucntive set of < and =).

If one says !(a < b) then one is saying A - {<}.

Joel