If I had the following SWI Prolog queries and answers
[A,B,C] ins 1..3, A#= B + C.
And needed to select from below which were incorrect:
A in 2..3,
B in 1..3,
C in 1..3.
Would I be correct in thinking that A in 2..3 is not possible as in no case can A = 3?
Actually, what the constraint does, is to reduce the domains of B and C.
Since their sum must be in range 1..3, and both have range 1..3. they must assume values in range 1..2.
Then A in 2..3 it's the only right answer there.