  We consider the following property:
  (*) For every function f from R^2 to R there are functions g_n,h_n from R to
R (for n<omega) such that for all real numbers x and y, f(x,y) = sum_{n<omega}
g_n(x)h_n(y).
  We show that, despite some expectation suggested by [Sh:675], (*) does not
imply MA(sigma-centered). Next, we introduce cardinal characteristics of the
continuum responsible for the failure of (*).
