We propose a formal description of individual preferences that captures a subsistence requirement in consumption in an otherwise standard constant-elasticity-ofsubstitution (CES) utility specification. We study how substitutability between the subsistence good and another good depends on the...

We characterize optimal consumption policies in a recursive intertemporal utility framework with local substitution. We establish existence and uniqueness and a version of the Kuhn-Tucker theorem characterizing the optimal consumption plan. An explicit solution is provided for the case when the...