Lafari@lemmy.world to

No Stupid Questions@lemmy.world · 10 months ago

Is "If A then B" equal to "B if and only if A"?

27

Is "If A then B" equal to "B if and only if A"?

Lafari@lemmy.world to

No Stupid Questions@lemmy.world · 10 months ago

Chat

zenharbinger@lemmy.world
link
fedilink
arrow-up
5·
edit-2
10 months ago
B can still be true when a is false. iff means that b can only be true when a is true.

Also, the equivalent statement is.

vehicle if and only if car.

not

car only if vehicle

since a truck is a vehicle, the statement is false.

Somewhat wrong above:

A B a iff b

T T T

T F F

F T F

F F T

look online for truth tables.

No Stupid Questions@lemmy.world

nostupidquestions@lemmy.world

You are not logged in. However you can subscribe from another Fediverse account, for example Lemmy or Mastodon. To do this, paste the following into the search field of your instance: !nostupidquestions@lemmy.world

No such thing. Ask away!

!nostupidquestions is a community dedicated to being helpful and answering each others’ questions on various topics.

The rules for posting and commenting, besides the rules defined here for lemmy.world, are as follows:

Rules (interactive)

Rule 1- All posts must be legitimate questions. All post titles must include a question.

All posts must be legitimate questions, and all post titles must include a question. Questions that are joke or trolling questions, memes, song lyrics as title, etc. are not allowed here. See Rule 6 for all exceptions.

Rule 2- Your question subject cannot be illegal or NSFW material.

Your question subject cannot be illegal or NSFW material. You will be warned first, banned second.

Rule 3- Do not seek mental, medical and professional help here.

Do not seek mental, medical and professional help here. Breaking this rule will not get you or your post removed, but it will put you at risk, and possibly in danger.

Rule 4- No self promotion or upvote-farming of any kind.

That’s it.

Rule 5- No baiting or sealioning or promoting an agenda.

Questions which, instead of being of an innocuous nature, are specifically intended (based on reports and in the opinion of our crack moderation team) to bait users into ideological wars on charged political topics will be removed and the authors warned - or banned - depending on severity.

Rule 6- Regarding META posts and joke questions.

Provided it is about the community itself, you may post non-question posts using the [META] tag on your post title.

On fridays, you are allowed to post meme and troll questions, on the condition that it’s in text format only, and conforms with our other rules. These posts MUST include the [NSQ Friday] tag in their title.

If you post a serious question on friday and are looking only for legitimate answers, then please include the [Serious] tag on your post. Irrelevant replies will then be removed by moderators.

Rule 7- You can't intentionally annoy, mock, or harass other members.

If you intentionally annoy, mock, harass, or discriminate against any individual member, you will be removed.

Likewise, if you are a member, sympathiser or a resemblant of a movement that is known to largely hate, mock, discriminate against, and/or want to take lives of a group of people, and you were provably vocal about your hate, then you will be banned on sight.

Rule 8- All comments should try to stay relevant to their parent content.

Rule 9- Reposts from other platforms are not allowed.

Let everyone have their own content.

Rule 10- Majority of bots aren't allowed to participate here.

Credits

Our breathtaking icon was bestowed upon us by @Cevilia!

The greatest banner of all time: by @TheOneWithTheHair!

Visibility: Public

This community can be federated to other instances and be posted/commented in by their users.

1.41K users / day
3.73K users / week
9.12K users / month
19K users / 6 months
1 local subscriber
35.8K subscribers
3.31K Posts
131K Comments
Modlog