Where

Optional list of boolean filter predicates. Each is a `tx.Expression` yielding a boolean (typically a `tx.Equals` / `tx.GreaterThan` / `tx.Contains` over a `tx.PropertyRead`, combined with `tx.And` / `tx.Or` / `tx.Not`), evaluated against the bound instance available as `input`. An instance is included only when every predicate holds; an absent `where` includes every instance of the bound class. Reusing the transformations predicate vocabulary keeps filtering in the one expression language rather than a parallel constraint grammar.