Categories of spaces may not be generalized spaces
as exemplified by directed graphs

F. William Lawvere

Originally published as:
Revista Colombiana de Matematicas, XX (1986) 179-186.

Keywords: topos of spaces, directed graphs, sheaves, idempotents, Mengen.

2000 MSC: 00A30, 14F20, 18B25, 18B30, 18B40, 55U40, 81P05

Republished in:
Reprints in Theory and Applications of Categories, No. 9 (2005) pp. 1-7