Function cumulative_reading 

pub fn cumulative_reading<'a>(
    expr: &'a LogicExpr<'a>,
    interner: &mut Interner,
    expr_arena: &'a Arena<LogicExpr<'a>>,
) -> Option<&'a LogicExpr<'a>>

Builds the CUMULATIVE reading (Scha 1981) for a two-cardinal transitive sentence — the reading irreducible to either nesting: “Three boys lifted five boxes.” → ∃=3 x(Boy(x) ∧ ∃y(Box(y) ∧ Lift(x,y))) ∧ ∃=5 y(Box(y) ∧ ∃x(Boy(x) ∧ Lift(x,y))) i.e. exactly 3 boys each lifted some box AND exactly 5 boxes were each lifted by some boy. This is first-order over the Link lattice (no ⊕ term needed). It is produced only when there are exactly two cardinal quantifiers in the same island over a shared nucleus; otherwise returns None.