Comfort, W.W.; Gotchev, Ivan S.; Recoder-Nuñez, Luis(Universitat Politècnica de València, 2008-10-01)
[EN] Let {Xi : i ∈ I} be a set of sets, XJ :=Пi∈J Xi when Ø ≠ J ⊆ I; Y be a subset of XI , Z be a set, and f : Y → Z. Then f is said to depend on J if p, q ∈ Y , pJ = qJ ⇒ f(p) = f(q); in this case, fJ : πJ [Y ] → Z is ...