At 07:12 local time, our observation began at the check point between the two halves of a city its administrators describe as one city. A teacher of mathematics presented her identification card, her residence permit, and her school access permit. Three documents, issued by the same administration, to move one person across a distance she walks in eleven minutes. At minute nine of the queue, the woman behind her apologized for the third time, though no party involved had caused the delay. By minute fourteen the queue had produced its fourth apology, directed at a turnstile.

The administration has tightened conditions on Palestinian schools in East Jerusalem, pairing the permit regime with pressure to replace the curriculum with the Israeli one. The mechanism is elegant: the classroom is reached through the check point, the check point recognizes permits, and the permits renew only for schools in compliance. The teachers who decline do not lose their classrooms. They lose the certainty of reaching them, and begin teaching the syllabus in whatever order the queue permits. Our subject reported covering fractions twice last term, because she could never guarantee which class the documents would let her attend.

A deputy spokesperson for the municipality, interviewed near the barrier, defended the arrangement. "An undivided city cannot supervise itself without records," he said. "If everyone carried proof of residence, proof of employment, and proof of purpose, the unity would be visible to all." He said this within sight of the wall.

The teachers have adapted with the competence the situation deserves. One, a resident of the neighborhood for four decades and a teacher at the same school for thirty-one years, showed us her folder: laminated copies sorted by checkpoint mood. She estimated its contents at forty pages. She had counted. Nobody had asked her to. "I was born here," she told us, arranging page four, "but the city prefers it in writing. So now I am from page four." She held the page up briefly, as one presents credentials, and put it back in the section marked calm mornings.

Our instrument recorded the full transit: three documents, two barriers, fifty-one minutes, four apologies, one accepted, zero questions about mathematics. On our world we administer populations by census alone and have never needed their consent to be counted; we assumed the practice was universal. Here the species has refined it. The counted now carry the count themselves, laminated, in triplicate, to prove they exist in the place they have always existed. She passed through at 08:03 and began her lesson at 08:06. The city is one city. She keeps the evidence in a folder.