>reading textbook >definition is stated >says "if"

>>8921902
Maybe it's not a biconditional. What's the definition?

"we say X if Y" in a definition means iff

>>8921904
it's 21 pages long

>>8921911
Either scan that shit or copy it in [math]\TeX[/math], the choice is yours.

>>8921904
This guy: >>8921911 is not me so idk what he meant by that.

I'm reading Understanding Analysis and I quote:

A set [math]A\subseteq\mathbb{R}[/math] is bounded above if there exists a number [math]b\in\mathbb{R}[/math] such that [math]a\leq b[/math] for all [math]a\in A[/math].

I've seen my professors casually do this all the time and it's stupid

>>8921902
This is (unfortunately) standard for definitions. And yes, it is rather confusing and annoying at first. But you just get used to it.

>>8921904
If it's truly a definition, then it is a biconditional.

>>8921948
By stating "if" the definition is not logically incorrect. In fact it's still perfectly valid.

It also avoids having to do the other half of the proof.

>>8921957
it's a definition though. it doesnt need proof

>OP writes "iff" in his definitions
Autism

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>>8921957
>definition
>proof

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>>8921902
>he abbreviates "if and only if" to "iff"

>>8921902
Yeah they mean if in an English language sense, not the logical sense when used in definitions.

Nobody says iff in definitions. Have you never read a math book before?

>>8921902
worst is when you have some definitions with "if and only if" and then others are just "if"

>>8921911
is this a new meme

>>8922158
There is literally no reason not to put the extra f in there.

>if
[You are here]
>iff
>iffst
>iffst'd've

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>>8922396
whoa