Rational fuzzy attribute logic.

We present a logic for reasoning with if-then formulas which involve constants for rational truth degrees from the unit interval. We introduce graded semantic and syntactic entailment of formulas. We prove the logic is complete in Pavelka style and depending on the choice of structure of truth degrees, the logic is a decidable fragment of the Rational Pavelka logic (RPL) or the Rational Product Logic (R{\Pi}L). We also present a characterization of the entailment based on least models and study related closure structures.