Three generations from topology

Generation structure is read from the topology of the T^2-fiber rather than postulated as a repeated particle table. The three generations correspond to the admissible fundamental-cycle structure of the fiber-mode grammar; a fourth generation would require a topology the carrier does not supply. The inspection question is not whether other topologies could be imagined, but whether any admissible τ-internal variation of the earned T^2-fiber changes the generation count.