Talk:Algebra of sets

message: :The following discussion is an archived debate of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section. 
The result of the debate was no move. -- tariqabjotu 02:30, 24 August 2006 (UTC)
thread_title: Untitled

message: Add "* Support" or "* Oppose" followed by an optional one-sentence explanation, then sign your opinion with ~~~~
*Oppose.  "Set algebra" might mean something completly different, and probably should redirect to Field of sets.  — Arthur Rubin |  (talk) 22:00, 14 August 2006 (UTC)
thread_title: Survey

message: There is no where in the article a definition of the "substruction" operation appearing, namely \
Diam - 18 Feb 2011
:See relative complement for the definition. Paul August ☎ 12:01, 18 February 2011 (UTC)
thread_title: Subtraction?

message: The article had a very didactic tone.  I have tried to make it more descriptive and less didactic.  I am not too happy with the numbered "propositions", though I can't put my finger on why. I suppose it's because it's not clear whether the article is taking a set-theoretic point of view, where these are consequences of logical definitions like A U B = {x | x in A or x in B}, or an algebraic point of view, in which case some of these are axioms and others are theorems. Under "proposition 3", it says that these results "can be derived from the five fundamental pairs...", but the fundamental pairs weren't defined as fundamental (except by the title of the section).  The article in general is trying to stay very elementary, but it wikilinks to Duality (order theory), which isn't very elementary.  Set difference is mentioned but not defined. --Macrakis (talk) 20:34, 14 September 2013 (UTC)
thread_title: Didactic tone

message: https://en.wikipedia.org/wiki/Algebra_of_sets#Sets_and_maps seems to be missing a definition of f^{-1}(X) --Intellec7 (talk) 05:20, 1 September 2020 (UTC)
replies: text: Added a link to preimage. - Jochen Burghardt (talk) 06:08, 1 September 2020 (UTC)
thread_title: Missing definition of f inverse 

message: "The union and intersection of sets may be seen as analogous to the addition and multiplication of numbers. Like addition and multiplication, the operations of union and intersection are commutative and associative, and intersection distributes over union. However, unlike addition and multiplication, union also distributes over intersection." Is the only sense of the analogy that multiplication distributes over addition? If so, then I think this should be removed. If the goal of making an analogy here is to explain to a reader what it means for an operation to distribute over another operation, I think that should probably be left for the article for the distributive property.
Perhaps it could be replaced in favor of another analogy:
\{1, 2, \ldots, n\} = S(n)
S(a) \cap S(b) = S(\min(a,b))
S(a) \cup S(b) = S(\max(a,b))
As far as I know, this is an isomorphism, so quite a bit more than an analogy, and might not necessarily help a reader understand at this point, but could be included in the article elsewhere. Note that \min and \max distribute over each other. --Intellec7 (talk) 16:33, 1 September 2020 (UTC)
replies: text: The analogy extends farther than just the distributive property, e.g A \cup \varnothing = A and A \cap \varnothing = \varnothing (where \varnothing is the analogue of zero), among others. Note also that the union of and intersection sets A and B is also called their "sum" and "product", and written A+B and AB. Paul August ☎ 17:23, 1 September 2020 (UTC)
thread_title: Questionable Analogy