3.5.1 Natural Deduction - Advanced Proofs

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  • Опубліковано 6 лис 2024

КОМЕНТАРІ • 17

  • @pabloperdo3293
    @pabloperdo3293 2 роки тому +1

    Really appreciating your work, you might as well have saved my exam!

  • @oneandonlyflow
    @oneandonlyflow 4 роки тому +4

    12:14 my professor said we aren't allowed to go from the conditional if p then q to not (p) OR q if we're just using the laws of natural deduction.

    • @morgard211
      @morgard211 4 роки тому

      Yes, I believe that you should do it by using assumptions.

    • @oneandonlyflow
      @oneandonlyflow 4 роки тому

      Tomáš Hauser yep this video isn’t actually correct

    • @noaag
      @noaag 4 роки тому +1

      For any students who see this, the video is correct. This is Material Implication and it's super important. Here is the example from my text, Intro to SL by Hurley:
      ...the statement “If you bother me, then I’ll punch you in the nose” (B⊃P) is logically equivalent to “Either you stop bothering me or I’ll punch you in the nose” (∼BvP).
      It makes perfect sense with other examples too. "If we emit a lot of CO2, then we will accelerate climate change" is equivalent to "Either we stop emitting a lot of CO2, or we will accelerate climate change".

  • @laurely9195
    @laurely9195 3 роки тому +2

    this is literally a different language

  • @lancelofjohn6995
    @lancelofjohn6995 3 роки тому

    in the last part c->~c,do we need to consider whether c is true or false?whether can false create true?c(false)->~c(true)? or c(true)->~c(flase),if c is false,then (c->~c) expression is true or not?

  • @lancelofjohn6995
    @lancelofjohn6995 3 роки тому

    If we use tautology to get the value of ~C, then we can think that ~C is true,right?

  • @brownsnoutspookfish
    @brownsnoutspookfish 3 роки тому

    hello, can someone really suggest a good book to start with?

  • @Recordingization
    @Recordingization 4 роки тому

    Hello ,thanks for the explanation.
    But I have obe question:
    How do you prove that ~CV~C deducts that ~C is true by using tautology?Could you please provide any proof or hint?

    • @morgard211
      @morgard211 4 роки тому

      When you have ~C, you can add another one: ~C v ~C. The same way you can take it away since the dysjunction has the same sides.

  • @michaelmcroy5103
    @michaelmcroy5103 3 роки тому

    youre making a lot of this more complex
    to prove a conditional start with assuming the antecedent and prove the consequent

  • @abisarwan20
    @abisarwan20 4 роки тому

    i dont understand about assumption.
    in any case, we can use it?
    can someone explain to me

    • @chexblu
      @chexblu 3 роки тому

      It's like you say, if I had a banana I could... And then you'd get out of the assumption saying by using one of the 3 ways of getting out of an assumption (I don't remember the names rn I'm sorry)

    • @abisarwan20
      @abisarwan20 3 роки тому +1

      @@chexblu thanks for explication !

    • @chexblu
      @chexblu 3 роки тому

      @@abisarwan20 Yw :3