Generative Structural Theory v1.8: Global Event Words and Compatibility Across the Full Threshold Line

Generative Structural Theory v1.8 studies the global compatibility of event states across an entire threshold line in finite non-negative relation-strength models. GST v1.6 classified the event state associated with a single positive critical value, while GST v1.7 classified the state associated with the zero boundary. The present paper asks which sequences of these local states can occur together in one model. For a model with mm positive critical values and a non-empty zero layer, the successive cuts form a strictly decreasing chain from the full relation set to the empty set. Its m+1m+1 transitions define a global event word. These words occupy only a small part of the direct product of the local event spectra: of 30 conceivable words for m=1m=1, only 5 occur; of 180 for m=2m=2, 21 occur; and of 1080 for m=3m=3, 81 occur. At length three, 46 words satisfy every realizable adjacent-pair condition, but only 21 are globally realizable, showing that pairwise compatibility does not characterize global realizability. Four structural laws are proved for every finite model: the number of letters that change N4 is even; T0T_0 is monotone and changes at most once; T1T_1 changes only at the final transition; and a transition that fails to preserve N4 forces N4 to fail immediately above it. These laws assemble into a finite automaton whose states record (N4,T0)(N4,T_0). The main result is stated in three deliberately separate forms: soundness for arbitrary mm; bounded completeness for 0≤m≤40≤ m≤4; and the reverse inclusion for arbitrary mm as a conjecture rather than a theorem. Explicit deposited witnesses are provided for all 405 automaton-accepted words in the proved bounded range. The accompanying reproducibility archive contains the complete source, verification programs, mutation batteries, generated tables, certificates, coverage records, and reference bundle. Thirteen verifiers and thirteen mutation batteries test 483 mutants with zero silent or rejected cases. The frozen archive is accompanied by a SHA-256 sidecar and a manifest covering every deposited payload file and the frozen PDF.