What the fuck is this shit? I am not a STEM.

>>7939133
Well I'm no expert, but they look like derivation rules for propositional logic.

[math]\varphi[/math] and [math}\psi[/math] stand for some propositions, I for "introduction", E for "elimination", the horizontal bar for the deduction associated to I or E and the funky symbols for logical connectives.

Just some rules for expressions you can use in proofs.

File: some lesser bullshit.jpg (2KB, 82x17px) Image search: [Google]

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>>7939141
I see.
Although I have no fucking clue how or when to use them, even for the simplest problems like pic related.

It's not hard to understand, you just have to know what rules the symbols represent.

>>7939160
Because you're too lazy to take 10 minutes to understand what the fucking symbols mean.

If you actually struggle with the concepts of basic logic, quit whatever you do and go flip burgers for a living.

What does the [math][\varphi]^n[/math] stuff mean? I know in the context of the box in the second row first column it's supposed to translate roughly to "If you assume [math]\varphi[/math] and can derive [math]\psi[/math], then you can introduce [math]\varphi \rightarrow \psi[/math]", but I'm a little confused as to what the [math]n[/math] is supposed to represent.

In the Reductio ad absurdum box they use the brackets without the n, what does that represent, and how is it different from the "not introduction" rule?

File: some more bullshit.jpg (7KB, 568x165px) Image search: [Google]

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>>7939252
I know what the symbols mean (if you're talking about phi psi ^ v -> etc.
My current problem is that the prof handed us these derivation rules and told us to go work on practice problems with them after a very tenuous explanation of how they work.

>>7939278
The 'n' is to note which step you used the introduction/elimination in.
The brackets.... seem to be what you want to end up with (working bottom to top), according to the answer sheet.

how to summon emma stone

>>7939299
Oh I see. So would a multiline box thing have

[statement a]^1
-------------------
[statement b]^2
-------------------
statement c
------------------- -> I(1-2)
a -> c

or maybe just I(1) or I(2)

and if you wanted to introduce b -> c, would it just be I(2)?

Also would you happen to have a similar sheet to the OP one for existential quantifiers ([math]\forall[/math] and [math]\exists[/math])?

>>7939355
That is a good question.
Here is the exercise set + solutions:
https://www.docdroid.net/8ITevhK/phil-2001-exercise-set-4-predicate-logic-derivations.pdf.html
Haven't used existential quantifiers with this yet.

at what level do you find things like this in university?
also, i'm a math hobbyist interested in foundations and logic stuff, is there a good book on this stuff (preferably with problems and solutions)?

>>7939421
You won't encounter these unless you're specifically delving into stuff involving them. It's a dull field though with everything coming to a standstill.

>>7939421
>>7939426
I am not involved in STEM in the least and took a random 2nd year philosophy course because I needed something easy to balance out my semester.
Ended up with a Prof who specializes in this stuff and thinks that math is the best philosophy.

>>7939437
be nice to that man, he is truly a diamond in the rough
nay, he is the cure for cancer in a festering field of steamy indian curry shit
i would give anything to have a professor that cares, except the extra $1500 required to go to a better college

>>7939278
>>7939299
I think the brackets are also used to signify when you are supposed to go to a sub-proof.

My guess is that the n is just the name of those particular brackets. That's atleast how I use them when proving stuff like (A->B)<->(~B->~A). Like, [~B]^1 and then deducing ~A, and then introducing implication and getting rid of 1, etc.