spherical polyhedron S = (V, F ;E): For a 2-connected planar graph GS = (V,ES), drawn without self-intersection on a sphere (or in the plane), we record the vertices as V and the regions as faces F , and rewrite the directed edges E as ordered 4-tuples e = 〈h, i; j, k〉, where the edge from vertex h to vertex i has face j on the right and face k on the left. (The reversed edge −e = 〈i, h; k, j〉 ...

Family Planning Perspectives effects of family planning programs on rates of births and abortions; and incentives for out-of-wedlock childbearing attributed to the Aid to Families with Dependent Children (AFDC) program. These questions reflect more general but perhaps less widely publicized issues that are well suited to economic analysis, such as the cost and accessibility of reproductive heal...