F.9:27 - C.29 mathematical-lens use relation

When a mathematical-lens use relies on cross-local meaning, first recover an actual F.9 Bridge. Then state the exact bounded-use claim for the lens direction, correspondence rule, and tolerated loss, and recover current reliance. Use C.29 for the mathematical object, LensMappingMode, preserved and lost structure, lens-use judgement, and actual lens use. A Bridge can make a lens interpretable without making any lens use occur.