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View Full Version : is this sufficient for a relation to be transitive


matticus
Jan21-08, 07:01 PM
in the book i'm reading it gives a set S={0,1,2,3}, and it says that the relation R where (m,n) \in R if m + n = 3, m,n \in S.

it says that this relation isn't transitive, but couldn't you give a vacuous argument for transitivity.

more specifically there are no x,y,z s.t. (x,y) and (y,z) are elements of the S, therefore the statement
if (x,y) and (y,z) are in S then (x,z) is in S should be true, right?

masnevets
Jan21-08, 08:11 PM
(0,3) and (3,0) are both in R, but (0,0) is not.

matticus
Jan21-08, 08:41 PM
thanks, i don't know how i missed that. i must have had myself fooled that the 3rd number had to be unique from the first, when clearly it doesn't.