Halls of Provisional Geometry

The Halls of Provisional Geometry are a complex of drafting chambers, apertures, and unstruck floors occupying the western shoulder of the central stack, entered in most registers simply as provisional rather than by floor number. They are the seat of the Office of Provisional Geometry and the origin of the doctrine of pre-originating conditions. Nothing in the Halls is finished. Figures drawn there are understood to be awaiting confirmation, and a line that holds its position for fewer than eleven cycles is not considered to have been drawn at all.

The Halls maintain no permanent survey of their own extent. Their dimensions are taken, where they must be taken, by comparison with the Survey of the Canted Halls, which the Ledger Halls receive annually and rarely reconcile.

Design and the provisional ink

Chambers in the Halls are drafted in a suspension known as provisional ink, which adheres to surfaces that do not yet exist. A figure drawn in provisional ink is visible to any observer standing in the Hall, but casts no shadow, occupies no measured area, and cannot be copied except by a custodian of static geometry working under witness. The ink is prepared in the sub-cellar and issued by the flask. Flasks are numbered, and an unnumbered flask is not to be carried above the fourth landing.

Apertures within the Halls are subject to stability reporting. Where any variance in the dimensional stability of a provisional aperture exceeds 0.02 Unitary Lengths per Cycle, the matter must be reported to the Office of Provisional Geometry under the terms set out in the Seventh Concordance. In practice the threshold is tested by lowering a plumb line and observing whether it returns. If the line returns at a different length, the aperture is closed for the day.

The dispute of 14,045

The Halls are chiefly known for the Halls of Provisional Geometry dispute of 14,045, heard before the Directorate of Preemptive Resource Allocation and settled, after eleven sessions, in the Halls' favour. The question was narrow: whether a figure drawn in provisional ink on a floor that did not yet exist could lawfully be stamped. The Directorate held that it could not, on the ground that allocation precedes drawing and no seal may be affixed to a thing that has not been given room.

"A chamber not yet built may not be sealed, however well it is drawn, for the seal would then be the only thing in it."

— Directorate of Preemptive Resource Allocation, submission to the Seventh Concordance, Annex 2

The Halls replied that the floor did not precede the figure but was called into being by it, and that the Directorate's position required the seal to act upon nothing. By the annexes of the Seventh Concordance, the Halls' reading prevailed, and the practice of stamping documents with a pre-originating seal was established. Records so sealed are held to have been valid before the moment of their sealing, and the Halls have never since been asked to explain how this is entered in a day-book.

Governance and the pre-originating seal

The Halls are administered by the Office of Provisional Geometry, which holds its warrant from the Ledger Halls and reports to them through the Bureau of Impossible Geometry. Every pre-originating seal carries a letter and a serial, and a seal struck without a serial is void but not recoverable — it may not be destroyed, since its destruction cannot be pre-dated. Unrecoverable seals are stored in the vestibule in numbered trays.

Jurisdiction over the approaches to the Halls of Equivocation is shared with the Bureau of Ambivalent Geometry, an arrangement the Concordances describe as settled and which has required an amending schedule in each of the last nine recensions. The boundary is marked by a brass strip across the landing. Documents are passed over the strip; they are not carried across it.

Disputed descent and the Cadastral Recension

There is no scholarly agreement on which floors the Halls occupy. The Second Cadastral Recension enters them at the eighth gallery of the western shoulder; the Fourth Cadastral Recension enters them twice, once at the eighth gallery and once, with a note of correction that corrects nothing, at the ninth. The Survey of Minor Halls, Vol. LXXII declines to decide the question, observing only that the Halls were found in the same place on each of nine visits.

A minority position, advanced by the Committee on Unstable Elevations and never formally answered, holds that the Halls are properly a set of conditions rather than a place, and that the dispute of 14,045 was therefore correctly brought before the Directorate, since one cannot allocate a place that is a condition. The Committee has requested a hearing since 14,061. Its requests are acknowledged, filed, and returned to it by the brass strip.

Access and standing orders

Visitors to the Halls are issued a provisional badge, which is collected on departure unless the visitor has already departed. The badge is then filed as pre-originating and the visitor is recorded as present until the next audit. This has happened four times, most recently in the winter of 14,072, when a clerk of the Sub-Bureau of Provisional Inquiry was entered as present for nine days after leaving and received a commendation for attendance.

Standing orders require that no chamber be swept while a figure in provisional ink is awaiting confirmation. The order was amended in 14,069 after a sweeper at the fourth landing cleared a corridor that had not yet been drawn, and has since been read as applying only to confirmed figures — which is to say, to nothing in the Halls.

The Halls hold no completed inventory. They hold the beginning of one, on Floor 207, which the Ledger Halls describe as "in good order and still being drawn" (Survey of the Canted Halls, 14,074).