http://ift.tt/2m73a7X The Boston subway is a complex system, spreading out from a focus at Park Street. On March 3rd, the Boylston shuttle went into service, tying together the seven principal lines, on four different levels. A day later, train 86 went missing on the Cambridge-Dorchester line. The Harvard algebraist R. Tupelo suggested the train might have hit a node, a singularity. By adding the Boylston shuttle, the connectivity of the subway system had become infinite… Never heard of this tragic incident? Time to read up on A.J. Deutsch ’s classic ‘A subway named Moebius’ from 1950. A 12 page pdf of this short story is available via the Rio Rancho Math Camp . The ‘explanation’ given in the story is that the Moebius strip has a singularity. Before you yell that this is impossible, have a look at this or that . A ‘non spatial network’ where ‘an exclusion principle operates’, Deutsch’s story says. Here’s another take. The train took the exceptional fiber branch, instead
