Talk:Logical disjunction

Notation addition

I wanted to suggest to add "The notation was introduced by Bertrand Russell and Alfred North Whitehead." to the notations section. Since I'm a co-author of the cited paper, I shouldn't do it myself. Richard Zach (talk) 16:20, 23 January 2024 (UTC)

References

what's that upmost expression supposed to mean?

a <or> b = a+b - ab ?!?

Please put it into words, esp. why it is on the top of the page.

Defining Disjunction With Arithmetic

Isn't it idiotic to define logical functors using arithmetic? This presupposes the definitions of arithmetic operations, not to mention a number system and seems wholly inappropriate in the context of logic.

Having covered arithmetic disjunctions at university many years ago I was looking for them here, maybe hoping for more detail. In maths they take the form -

If x in range n Then y = f1(x) Else y = f2(x) . In maths they are often considered extremely poisonous because they create points of infinite rate of change where the rules of calculus break down, they make proof and logic 'impure' for the same reason. As I understand it they are often regarded as sticking plasters fixing over broken areas and are found everywhere in some places- like trigonometry, or anywhere where a lot of infinities occur. - My point is that they obviously need a page. Lucien86 (talk) 19:18, 23 August 2008 (UTC)

Unknown User

Yes, I think Disjunctive should be mergered with Logical disjunction

Formulas that don't duplicate a, b

a <or> b = 1 - (1-a)(1-b) = (a-1)(1-b) + 1

70.190.166.108 (talk) 18:06, 15 January 2017 (UTC)

OR gate symbol is not in accordance with MIL-STD-806b

The output side is too pointy and straight sided - other wikipedia articles show a different form for the gate symbol and should probably be used so as to be consistant. ChardingLLNL 22:54, 15 May 2006 (UTC)

Also, there is not a discussion/symbol/circuit for wired-OR operation. While logically not much different from a traditional OR gate it can support tri-state or powered off operations and thus operates beyond a simple boolean model. For more detail: [1]. --MountainLogic (talk) 16:28, 22 April 2008 (UTC)

The article logic gate is more appropriate for discussion of variants, since this article is about the abstract logical concept. The diagram should still be consistent though. Dcoetzee 16:57, 22 April 2008 (UTC)

a disambiguation?

maybe there should be a disambiguation so as to offer a redirect to Søren Kierkegaard's book? —The preceding unsigned comment was added by 70.130.34.235 (talk) 20:24, 9 April 2007 (UTC).

Proposed project

I have been working on all of the logical operators recently. I would like to see a consistent format for them. There is a wikiproject proposal for this at: Wikipedia:WikiProject_Council/Proposals#Logical_Operators. Also see Talk:Logical connective.

I would like to see the logical, grammatical, mathematical, and computer science applications of all of the operators on the single page for each of those concepts.

Gregbard 08:52, 28 June 2007 (UTC)

Yes, it seems clear that the the inclusive "or" and the exclusive "or" have different meanings, since their truth conditions are different. (Another point is that "either ... or ..." seems to me to indicate only the exclusive or, contrary to what the text suggests, but that's another issue.) Cubefox (talk) 19:38, 16 January 2020 (UTC)

Rename it to Inclusive Or

We should rename the article to "Inclusive Or", in accordance to Exclusive or.

More people understand what it means (articles like "water" are called "water", because it is understood by all, while "dihydrogen monoxide" is not)

Most people understand "Inclusive Or", but few will understand "logical disjunction". — Preceding unsigned comment added by RicardAnufriev (talk • contribs) 23:32, 28 September 2013 (UTC)

On the contrary, "inclusive or" is much more uncommon and confusing, since no one refers to it as the "inclusive or" except specifically to draw a comparison with the exclusive or. The general and common term in both mathematical logic and computer science for the subject of this article is "logical disjunction". —Lowellian (reply) 21:48, 21 April 2014 (UTC)

I don't think "disjunctor" should redirect here

As far as I can tell, a disjunctor can be either a botanical structure between conidia, or kind of electrical circuit-breaker. I don't think it has anything to do with logical disjunction. Equinox (talk) 21:11, 8 August 2015 (UTC)

Meaning of 'or' in language

I'm not feeling quite sure of myself to simply revert it, but in this edit Cubefox changed the last sentence of § Natural language to read:

In other words, in ordinary language "or" (even if used with "either") can mean either the inclusive "or" [exclusive-]or the exclusive "or."
— Logical disjunction 05:27, 2 August 2019 (UTC)

The change from the previous version (which read ...can mean either the inclusive or [inclusive-]or the exclusive or.) was explained in Cubefox's edit summary: We can mean either the inclusive "or" or the exclusive "or", but not both..

Except... "in ordinary language" or can (and does) have both meanings. It may be used both ways even in the same sentence, with only context and assumptions to indicate which sense is intended by any given use. So, exclusive or inclusive? -- FeRDNYC (talk) 05:27, 2 August 2019 (UTC)

@FeRDNYC: I think, Cubefox meant that when one particular speaker uses "P or Q" in one particular situation, (s)he should have a clear intention whether "P and Q" is included in the meaning, or not.

I'd agree to that, except for thoughtless everyday utterances (including by myself) - they are often understood as intended even if a negation is missing (e.g. in "I won't help you another time until I don't get my money back"). - Jochen Burghardt (talk) 07:31, 2 August 2019 (UTC)

truth table: 0111 vs TTTF

The information on the right (below "definition: x + y") and the table in the article show the values of its truth tables in reverse --Backinstadiums (talk) 10:28, 19 December 2019 (UTC)

Summary is too technical

This summary does not meet the wikipedia guidelines that the lead section be nontechnical if possible. https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Lead_section#Provide_an_accessible_overview — Preceding unsigned comment added by Idontusenumbers (talk • contribs) 19:54, 13 May 2021 (UTC)

I would agree. I would have liked to nominate the first paragraph for the honor of "worst Wikipedia introduction," but there are so may many other contenders it may not be a winner. But it is nearly unintelligible if you don't already understand the subject.

Important point for math nerds here: Rigorous logical correctness is fine its place, but the purpose of an encyclopedia is to be readable by amateurs.Skepticalgiraffe (talk) 15:53, 20 July 2022 (UTC)

My first reaction to this discussion is to say WP:SOFIXIT: you two are in a better position to say what you find difficult to understand than I: I can see that it's unnecessary to make the detour to proof theoretical in the lead, but otherwise I'm not sure what you are talking about. From my point of view the main problem with the lead lies in another direction; to me it seems more vague than precise: it doesn't fix what disjunction is, only what sort of thing it is. But doing that is often tricky in logic articles. — Charles Stewart (talk) 13:43, 21 July 2022 (UTC)

Logical disjunction was a good name

@TennisFans: You renamed this article to "Disjunction (logical connective)". I have no idea why, and I think it should be moved back. You should have at least brought it up on the talk page before. (And please do not rename Logical conjunction.) Watchduck (quack) 21:53, 5 August 2023 (UTC)

In most textbooks of logic, “disjunction” is the most standard name of the connective which is used most frequently, and “alternation” "logical or" “logical sum” “logical addition” “inclusive disjunction” “inclusive alternation” "inclusive or" “weak disjunction” “weak alternation” are sometimes seen literally too. While I seldom see “logical disjunction” literally which may be because disjunction itself is logical or used as a connective possibly only in the subject related to logic. The case of conjunction is similar while it's not successful to rename "Logical conjunction" into "Conjunction (logical connective) last time. @Liz: see the comments here.TennisFans (talk) 14:35, 7 August 2023 (UTC)

I have created a request to speedily delete the redirect page Logical disjunction (and the corresponding talk page), so the article can be named back. As far as I can see in the history, it had the name Logical disjunction since its creation in 2001. --Watchduck (quack) 09:09, 7 August 2023 (UTC)

Is there any reason the title shouldn't be simply "disjunction"? That's the most standard term and since that page is currently a redirect to this one, it doesn't seem like anybody's disputing primary topic. Botterweg14 (talk) 18:07, 8 August 2023 (UTC)

One reason might be that the main (or even all?) articles about junctors should follow a unique naming scheme, and e.g. Conjunction leads to a disambiguation page. - Jochen Burghardt (talk) 18:28, 8 August 2023 (UTC)

That's one of the reason that I rename the article as "Disjunction (logical connective)". TennisFans (talk) 07:36, 9 August 2023 (UTC)