  We give a simple algebraic characterisation of the sectional category of
rational maps admitting a homotopy retraction. As a particular case we get the
F\'elix-Halperin theorem for rational Lusternik-Schnirelmann category and prove
the conjecture of Jessup-Murillo-Parent on rational topological complexity. We
also give a characterisation for relative category in the sense of Doeraene-El
Haouari.
