Excluded-volume Effects In Linear-polymers - Universality of Generalized Self-avoiding Walks

A random walk which can visit each lattice site at most twice is considered. The universality of self-avoiding-walk critical behavior with respect to variations of a fugacity for self-intersections is predicted on the basis of general renormalization-group arguments and explicitly tested in two dimensions, both by exact enumeration analysis and by cluster scaling calculations. The meaning of the above universality and its consequences, as far as a correct formulation of Flory approximations is concerned, are briefly discussed.