Based on a stochastic extension of Karamata’s theory of slowly varying functions, necessary and sufficient conditions are
established for weak laws of large numbers for arbitrary linear combinations of independent and identically distributed nonnegative
random variables. The class of applicable distributions, herein described, extends beyond that for sample means, but even
for sample means our theory offers new results concerning the characterization of explicit norming sequences. The general
form of the latter characterization for linear combinations also yields a surprising new result in the theory of slow variation.
Summary General linear combinations of independent winnings in generalized \St~Petersburg games are interpreted as individual gains that result from pooling strategies of different cooperative players. A weak law of large numbers is proved for all such combinations, along with some almost sure results for the smallest and largest accumulation points, and a considerable body of earlier literature is fitted into this cooperative framework. Corresponding weak laws are also established, both conditionally and unconditionally, for random pooling strategies.