$ R = \{ (a,b) ∈\Bbb R^2 ; 1 + ab > 0 \} $
It is clearly reflexive and symmetrical but I feel that it is transitive also because the relation R can be stated as $ R = \{(0,0), (0,1), (1,2)...\}$ and as per the rules of transitive $ x,y ; y,z ; x,z = true $, and in the relation R it is true also, $ (0,1) $. Then why is not transitive? Are there some specific rules regarding $(0,0)$?
No it is not transitive consider $(-1, 1/2)$ and $(1/2,100)$.