Abstract. This paper contains an improved version of existing generalized central limit theorems for convergence of normalized sums of independent random variables distributed by a signed measure. It is shown that under reasonable conditions, the normalized sums converge in distribution to "higher-order" analogues of the standard normal random variable, in the sense that the density of the limiting signed distribution is the fundamental solution of a higher-order parabolic partial differential equation that is a generalization of the heat equation.1. Introduction. Probability theory is often thought of as the study of nonnegative bounded measures. However, several theorems usually considered to be purely probabilistic are, in fact, true in more general contexts. Specifically, several authors have extended such results to signed measures. For example, Hochberg [4] derives generalizations of the Brownian motion or Wiener process to higher-order signed stochastic processes, an analogue of the Itô stochastic calculus for these signed processes, and a probabilistic-style analysis of the spectral properties of higherorder elliptic operators.Similarly, the central limit theorem for convergence of normalized sums of random variables to the Gaussian distribution has been extended to the case where the random functions are distributed by a signed measure. Zukov [8] derives such a theorem for difference operators in a study of a problem in numerical analysis. Studnev [6] states, without proof, other generalizations, with an application to probability theory itself. Hersh [3] gives a more complete study of generalized central limit theorems, though his results do not apply to the cases n = 0 (mod 2) in what follows; that is, Hersh's theorems exclude the cases where the signed distribution has a density function which is the fundamental solution of the parabolic partial differential equation (2) below whose order is a multiple of four. Our techniques include these cases.In an earlier paper (Hochberg [4]), we derived two such central limit theorems, which we restate in the following two propositions. Here