Published online by Cambridge University Press: 20 November 2018
Let L 1, L 2 ⊂ Cn be two totally real subspaces of real dimension n, and such that L 1 ∩ L 2 = {0}. We show that continuous functions on L 1 ∪L 2 allow Carleman approximation by entire functions if and only if L 1 ∪L 2 is polynomially convex. If the latter condition is satisfied, then a function f:L 1 ∪L 2 —> C such that f|L iCk(Li), i = 1,2, allows Carleman approximation of order k by entire functions if and only if f satisfies the Cauchy-Riemann equations up to order k at the origin.