The Inimitable Tiff

Let Φ (a physical possibility structure) be a set of distinct but intersecting paths j_i–j_n, each of which is a set of functions, L’s, on ordered pairs {t, w} ({time, world situation}), such that for any L_n, L_m in some j_i, L_n R L_m, where R is a primitive accessibility relation corresponding to physical possibility understood in terms of diachronic physical compatibility.