Status: OUT
The combination of stdlib-delegated exact data structures (Counter for exact frequencies, set for exact membership) and construction-based exact arithmetic (isqrt, integer division, sentinel initialization) should prevent all precision-related errors across the repo.
exactness at both the stdlib and arithmetic layers should be comprehensive, but the tax computation uses float division — a known breach of the exact-arithmetic convention
Depends on (SL): stdlib-reinforces-exactness, correctness-by-construction-not-validation
Unless: tax-float-division-imprecision