Talk:Abstract Algebra/Sets

It may look less threatening if it has more diagrams.

--Arydye001 (talk) 05:48, 18 July 2010 (UTC)

The concept of set functions appears in the discussion of exponentials as Cartesian products. It might be better to introduce exponentials after the section on functions. Bronco creek (discuss • contribs) 20:43, 3 July 2020 (UTC)

The definition of a disjoint union given in Wikipedia is clearer than the one used here. Especially given that the concept of an indexed set is introduced in the preceding section on Cartesian products, I'd suggest using this:

Formally, let {A_i : i ∈ I} be a family of sets indexed by I. The disjoint union of this family is the set

$\bigsqcup _{i\in I}A_{i}=\bigcup _{i\in I}\{(x,i):x\in A_{i}\}.$

The elements of the disjoint union are ordered pairs (x, i). Here i serves as an auxiliary index that indicates which A_i the element x came from.

Bronco creek (discuss • contribs) 21:16, 3 July 2020 (UTC)