The Kyrie kept its name and lost its verses

Claim (verbatim)

The purge of the tropes was not uniform, and the survivors reveal its logic. Proper tropes - those wrapped around the Introit, Offertory, and Communion, the changing chants of the mass - were annihilated, surviving into no printed liturgy. Ordinary tropes fared differently: the trope verses of the Kyrie and Gloria were stripped, but their melodies survived, because those melodies had become the identity of particular mass-ordinary settings. The Tridentine Kyriale still labels its Kyrie melodies with the incipits of their vanished tropes - Kyrie fons bonitatis, Kyrie cunctipotens genitor Deus - names that are the ghosts of suppressed trope texts riding on melodies that outlived them. The mechanism is that an Ordinary trope's melody was reusable, cyclic, and detachable from its words, so it could survive as a titled tune when the words were cut, while a Proper trope was welded to one feast's one chant and had nowhere to go. Melody survived where it had become an index; text-and-melody died together where they had not. Prediction restated: within the Corpus Troporum repertory, the fraction of Ordinary (Kyrie and Gloria) trope melodies with a titled post-Trent descendant in the Kyriale exceeds the fraction of Proper (Introit) trope elements with any post-Trent survival by at least ten to one.

Prediction clause (verbatim)

Prediction: within the Corpus Troporum repertory, the fraction of Ordinary trope melodies (Kyrie and Gloria) that have a titled descendant melody in the post-Trent Kyriale exceeds the fraction of Proper (Introit) trope elements with any post-Trent survival by at least a factor of 10 (primary clause: the at-least-10x Ordinary-over-Proper trope survival ratio; the verdict follows it). Survival of an Ordinary trope counts when its melody carries into the Kyriale even with verses stripped, identified by the retained incipit-name; coverage guard: Proper-trope survival is effectively zero so the ratio is bounded below by the Ordinary survival rate alone, and the test voids only if fewer than 50 named Ordinary trope melodies can be matched to the Kyriale.

Kill-dataset (verbatim)

Kill (partly built): the Corpus Troporum inventories of Kyrie and Gloria tropes matched by retained melody-name to the post-Trent Vatican Kyriale, against the Corpus Troporum Introit-trope inventory matched to the post-Trent Proper; the operation is a differential survival ratio, Ordinary trope versus Proper trope.

Novelty / leakage triage

already answered in the literature

The differential is stated in the standard literature and in the liturgical books themselves: the Vatican Kyriale labels its melodies with the incipits of suppressed tropes (Kyrie fons bonitatis, Cunctipotens genitor Deus), the Melnicki and Bosse melody catalogues document the medieval Kyrie and Gloria trope-melody identities behind those titles, and proper-trope survival into any printed liturgy is zero. With the Proper side zero in print and the Ordinary side demonstrably nonzero in print, the 10x ratio of the primary clause is guaranteed; the only uncomputed quantity - the exact Ordinary survival fraction - cannot change the verdict.

• M. Landwehr-Melnicki, Das einstimmige Kyrie des lateinischen Mittelalters (Regensburg, 1955)
• D. Bosse, Untersuchung einstimmiger mittelalterlicher Melodien zum 'Gloria in excelsis Deo' (Regensburg, 1955)
• Kyriale seu Ordinarium Missae (Editio Vaticana; Rome, 1905)
• D. Hiley, Western Plainchant: A Handbook (Oxford, 1993), on Kyrie melodies and their trope titles

Predictions

No prediction registered yet.