Dimensional reduction and flavor chirality

We show that phenomenologically realistic flavor-chiral Yang-Mills-Higgs theories in 4 dimensions can be derived by dimensional reduction of 10-dimensional vectorlike and gauge theories, where the extra 6 dimensions form a compact coset space with scale size r. The dimensional reduction often implies a symmetry breaking pattern like that of the electroweak theory, in which case it is natural to propose r approx.= Gsub(F)sup(1/2). Quantum effects then determine the short-distance behavior of the theory, including any additional symmetry breaking. (orig.)