An Efficient and Precise Finite-Tree Analysis for Constraint Logic-Based Languages

projection on the composite domain H × P is much simpler thanabstract unification, because in this case there is no interaction between the twocomponents of the abstract domain. Definition 20. (Abstract projection on H×P .) The function projH : H×VI → H captures the effects, on the H component, of projecting away a variable.For each h ∈ H and x ∈ VI , projH(h, x) def= h ∪ {x}. 10Let t be y. Let also P be Pos. Then, given the Pos formula φdef= (x ∨ y), both indφ(x, y)and or linφ(x, y) satisfy the conditions in Definition 4. Note that from φ we cannot infer that xis definitely linear and neither that y is definitely linear.