Terminal Trigram Repetition in Phaistos Disk Inscription Side A: Quantitative Evidence for Structural Closure at Positions A28 and A31

The Phaistos Disk (Heraklion Archaeological Museum) Side A contains 31 impressed sign-groups arranged in a spiral. Systematic positional analysis identifies an identical ordered trigram at field A28 and field A31. The trigram comprises Sign i, Sign j, and Sign k, where k corresponds to Evans Numeral 38 'flower/lotus'. Field A28 marks the completion of four 7-field sequences. Field A31 is the terminal field of the inscription. Binomial probability of identical trigram repetition in these positions under random distribution: p = 2.14 × 10⁻⁵. Side A commences with four impressed dot markers. Recurrent sign pairs occur in fields A1, A5, A8, A10, A12, A16, A17, A19, A22, A23, A26. No linguistic decipherment or semantic assignment is proposed. The positional and statistical data indicate non-random structural organization consistent with formal closure formulas. Dataset and positional matrix available upon request.