Theorem 12.2

Theorem 12.2 (Direct palindrome construction). For a persistent sequence implementation satisfying the contract of Section 11.1, the receipt construction recognizes the binary even-palindrome language with a finite scaffolding automaton. If the complete client has source-record bounds $(A_*,q,R_*)$, it has degree $\max\{1,2+A_*q\}$ and distance at most $R_*+1$.