Closed Loop — The Tower

The Closed Loop is the certification form by which a procedure, document, or installation is shown to satisfy the Principle of the Closed Loop without recourse to any authority originating beyond itself. A Closed Loop consists of a citation, a verification of that citation, and a final certification which cites the verification — the three elements referring in sequence to one another and to nothing else. Once the third element is sealed, the Loop is closed, and the file may be stamped with the Omega Seal and lodged at Annex Omega. A Loop that requires an outside authority to remain valid is not a Closed Loop but a dangling reference, and is returned unsealed with a Form 12 (Objection to Openness).

The form is ancient; the phrase itself appears in the Second Recension of the Concordances, and the procedure has been administered since the founding of the Scribes of the Closed Loop, whose Sigil of the Closed Fist is affixed to every completed Loop Map. Certification is conducted only by accredited Scribes; a Loop Map submitted by an unaccredited hand is void regardless of whether it closes.

Structure and terminology

A Closed Loop is drawn as a circle in the margin of its own first page. Along the circumference the Scribe inscribes three marks, corresponding to the citation, the verification, and the certification. The circle is then closed at the point where it began, and the Scribe's seal placed over the join so that the seam cannot be identified. The purpose of sealing the join is procedural rather than decorative: a Loop whose seam remains visible may be reopened, and a Loop that may be reopened is, by definition, not closed.

Terminology within the Scribes distinguishes the closing of a Loop, which is the act of sealing, from the completion of a Loop, which is the act of recording the closing in the register. The two are frequently confused in correspondence. The Division of Terminal Verifications maintains that only completion confers standing; the Office of Reciprocal Citation maintains that closing is sufficient and completion is merely clerical. The dispute has been referred to Concordance 44 on six occasions and returned unresolved each time.

Procedure

An applicant submits a Loop Map to the nearest accredited Scribe, together with a declaration that the Map's citations terminate within itself. The Scribe traces the Map once in each direction; a Map that cannot be traced in both directions is returned. The Scribe then affixes the seal and records the closing in the register, noting the floor, the hour, and the number of the Map. The applicant receives a certified copy of the Map and the original is retained at Annex Omega.

Where a Map cites a document that has not itself been closed, the Scribe may issue a provisional seal valid for ninety days, during which the cited document must be closed or the provisional seal lapses. Provisional seals are recorded in red. The red ink is not symbolic; it is required by Concordance 61 so that lapsed Loops may be identified without reading the text. Clerks are reminded that red ink is reserved for this purpose and may not be used for emphasis. This rule is broken most often by clerks emphasising the rule.

The Great Reopening and the Scribes' objection

In the winter of the year the Tower records as 3,118 — the year is disputed; the Sub-lateral Chronology places it four years earlier — a body of Scribes at Aperture 303 undertook to reopen and re-close every Loop certified in the preceding decade. The stated grounds were that several Loops had been sealed over joins that were not the seams originally drawn, meaning the circles had closed on the wrong element and certified a sequence that did not in fact terminate. The number of affected Loops was reported as either eleven or four thousand and nine, depending on whether one counted certified copies.

"A Loop closed over the wrong seam is worse than an open one, for an open one at least knows it is unfinished."

— Scribes of the Closed Loop, Minutes of the Aperture 303 Session, fol. 41r

The Division of Terminal Verifications objected that reopening a closed Loop violated the Principle of the Closed Loop itself, since a Loop that may be reopened was never closed and its certification had therefore always been invalid — an objection which, if upheld, would have voided the entire register. The matter was settled by Clause Omega-7, which permits reopening only where the original seam can be shown to have been misdrawn, and provides that the resulting Loop is deemed to have been closed continuously since its first sealing. Eleven Loops were reopened. The remainder of the four thousand and nine were certified as having been closed correctly and the discrepancy was entered in the margin.

Relation to recursive citation

The Closed Loop is often confused with the Recursive Citation Loop, in which a document cites a second document that cites the first. The distinction is that a Recursive Citation Loop may remain open indefinitely, each citation leading to the next without resolution, whereas a Closed Loop must terminate. A document caught in a Recursive Citation Loop cannot be certified until the loop is broken or converted; the conversion procedure is set out in Recursive Loop Certification. The Precedential Loop of Elara Vance is the most-cited example of a Loop that was certified only after three centuries of open recursion.

The Recursive Certification Loop is a distinct pathology affecting the certifying office itself rather than the document, and is treated separately.

Objections and open questions

A minority of Librarians, chiefly those attached to the Sub-lateral Chronology, hold that no Loop can be closed in the strict sense, since the act of sealing is itself an event requiring a date, and a date is an external reference. This objection has never been formally answered. It has instead been absorbed: since Concordance 77, the date is considered internal to the seal rather than to the Loop, and the Loop remains closed. The minority regards this as a distinction without a difference and continues to withhold its countersignature, which is not required.

Completed Loops are filed flat and may not be folded. A folded Loop Map is presumed to have been carried in a pocket and is subject to re-verification at the applicant's expense.