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58658
Fri 27 Nov, 2009 04:57 pm
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a kind person directed me here from the welcome threads to pose my questions for logic. i have a few problems that i have been boggling over within this week. each have to be solved using only the rules of inference. as obvious as it may be, i am very new to this and i am trying to understand. any help would be greatly appreciated!
1. O ⊃ P P ⊃ ~P __________ |- ~O 2. S /// (three-tier equal symbol) Q ~S ___________________ |- ~Q 3. T __________ |- S ⊃ T 4. W . (X v Y) ~W v ~X ____________ |- W . Y :perplexed: |
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58659
Fri 27 Nov, 2009 05:07 pm
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Don't you have a textbook? This is quite basic stuff and you should be able to figure it out simply by reading a textbook. I could do the proofs for you, but what would that help?
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58660
Fri 27 Nov, 2009 05:23 pm
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that's just it, i don't understand the text book! i read the chapter and none of it makes sense. i am attempting to find a tutor i can contact. i understand your argument, however! i said "any help" so encouraging me to read perhaps falls under that category too.
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58661
Fri 27 Nov, 2009 05:42 pm
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mrmicr;106473 wrote:
I can send you another textbook if you want. Just PM me your email. |
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58662
Fri 27 Nov, 2009 08:23 pm
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ok, i looked over my notes and skimmed the text book that you sent. please let me know if i'm on the right track with what i've done thus far.
1. O ⊃ P 2. P ⊃ ~P 3. ~P v ~P 2, impl 4. ~P 3, taut 5. ~O 1,4, mt 1. S <-> Q 2. ~S 3. (S ⊃ Q) & (Q ⊃ S) 1, equiv 4. (Q ⊃ S) & (S ⊃ Q) 3, com 5. Q ⊃ S 4, simp 6. ~Q 2,5, mt 1. T 2. T v ~S 1, add 3. ~S v T 2, com 4. S ⊃ T 3, impl |
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58663
Sat 28 Nov, 2009 08:39 am
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mrmicr;106522 wrote:
Symbols available here. You are doing it correctly. :a-ok: Though step (4) in proof (2) is redundant. You don't need to turn it around first to use simplification. |
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58664
Mon 30 Nov, 2009 08:17 pm
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I need help with a proof!:perplexed:
It was on my test today so I am just curious how to solve it. I pretty much know what I am doing, but this one has me stumped!:brickwall: $=existential @=Universal ($xPx v $xQx), @y(Py -> ~Ry) |- (@xRx -> $xQx) Can anyone help? I only know primitive rules. Thanks! |
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58665
Tue 1 Dec, 2009 01:33 am
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Symbols available here.
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