Zero-ULP Fixed-Point Statutory Computation and Client-Side WebAssembly Isolation for Cross-Jurisdictional Regulatory Audit Engines

Cross-jurisdictional statutory compliance and forensic accounting engines evaluate discontinuous legal threshold predicates ('statutory cliffs') over multi-million-line enterprise ledgers while handling confidential tax, customs, carbon, clinical, and cryptographic records. Conventional cloud SaaS platforms and desktop spreadsheets suffer from two foundational architectural defects: (1) executing decimal statutory formulas inside radix-2 IEEE Std 754-2019 binary64 floating-point arithmetic—where elementary decimal constants such as 0.1_10 incur exact representation error (+1 / 180,143,985,094,819,840) and non-associative summation (a + b) + c != a + (b + c) causes row-ordering permutations to flip statutory cliff classifications and cents—and (2) requiring enterprises to upload confidential ledgers into multi-tenant vendor servers, breaking data-residency and privilege boundaries. Serving as the architectural capstone for the TITAN statutory verification series (TITAN-WP-2026-01 through 14), this monograph formalizes: (i) an exact scaled-integer ring Z_S and coprime rational kernel Q with jurisdiction-parameterized terminal rounding morphisms achieving 0-ULP permutation invariance, (ii) a capability-zero client-side WebAssembly (Wasm 2.0) host-isolation model satisfying strict outbound network non-interference, and (iii) self-authenticating cryptographic docket sealing under U.S. Federal Rules of Evidence 902(13)–(14) and EU eIDAS 2.0 (Regulation (EU) 2024/1183). Reference Verification Implementation: https://titancapitalforensics.com (Maintained by TITAN Capital Forensics LLC, Albuquerque, New Mexico, USA; D-U-N-S: 33-195-8002; UNGM: #1299169). Zero source code or executable software distributed.