Equivalent sets of wffs












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Propositional logic. Given two sets of wffs, $Sigma$ and $Gamma$, are the following definitions of equivalence between $Sigma$ and $Gamma$ .....equivalent?




  1. $(SigmavDashGamma)land(GammavDashSigma)$


  2. For all $alpha$, $(SigmavDashalpha)leftrightarrow(GammavDashalpha)$



I'm not looking for a proof, a just want to avoid engaging myself in a lost battle.










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$endgroup$

















    1












    $begingroup$


    Propositional logic. Given two sets of wffs, $Sigma$ and $Gamma$, are the following definitions of equivalence between $Sigma$ and $Gamma$ .....equivalent?




    1. $(SigmavDashGamma)land(GammavDashSigma)$


    2. For all $alpha$, $(SigmavDashalpha)leftrightarrow(GammavDashalpha)$



    I'm not looking for a proof, a just want to avoid engaging myself in a lost battle.










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      Propositional logic. Given two sets of wffs, $Sigma$ and $Gamma$, are the following definitions of equivalence between $Sigma$ and $Gamma$ .....equivalent?




      1. $(SigmavDashGamma)land(GammavDashSigma)$


      2. For all $alpha$, $(SigmavDashalpha)leftrightarrow(GammavDashalpha)$



      I'm not looking for a proof, a just want to avoid engaging myself in a lost battle.










      share|cite|improve this question









      $endgroup$




      Propositional logic. Given two sets of wffs, $Sigma$ and $Gamma$, are the following definitions of equivalence between $Sigma$ and $Gamma$ .....equivalent?




      1. $(SigmavDashGamma)land(GammavDashSigma)$


      2. For all $alpha$, $(SigmavDashalpha)leftrightarrow(GammavDashalpha)$



      I'm not looking for a proof, a just want to avoid engaging myself in a lost battle.







      propositional-calculus






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      asked Jan 25 at 19:49









      PeptideChainPeptideChain

      464311




      464311






















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          $begingroup$

          Two sets of formulas are equivalent, if any formula of the one set is a consequence of the other and conversely.



          Equivalently, they have the same models.



          This means :




          $text {for every } alpha in Gamma : Sigma vDash alpha$ and $text { for every } beta in Sigma : Gamma vDash beta$.







          share|cite|improve this answer









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          • $begingroup$
            Is there any relation with the two expressions in the Q?
            $endgroup$
            – PeptideChain
            Jan 25 at 20:12











          Your Answer





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          1 Answer
          1






          active

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          1












          $begingroup$

          Two sets of formulas are equivalent, if any formula of the one set is a consequence of the other and conversely.



          Equivalently, they have the same models.



          This means :




          $text {for every } alpha in Gamma : Sigma vDash alpha$ and $text { for every } beta in Sigma : Gamma vDash beta$.







          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Is there any relation with the two expressions in the Q?
            $endgroup$
            – PeptideChain
            Jan 25 at 20:12
















          1












          $begingroup$

          Two sets of formulas are equivalent, if any formula of the one set is a consequence of the other and conversely.



          Equivalently, they have the same models.



          This means :




          $text {for every } alpha in Gamma : Sigma vDash alpha$ and $text { for every } beta in Sigma : Gamma vDash beta$.







          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Is there any relation with the two expressions in the Q?
            $endgroup$
            – PeptideChain
            Jan 25 at 20:12














          1












          1








          1





          $begingroup$

          Two sets of formulas are equivalent, if any formula of the one set is a consequence of the other and conversely.



          Equivalently, they have the same models.



          This means :




          $text {for every } alpha in Gamma : Sigma vDash alpha$ and $text { for every } beta in Sigma : Gamma vDash beta$.







          share|cite|improve this answer









          $endgroup$



          Two sets of formulas are equivalent, if any formula of the one set is a consequence of the other and conversely.



          Equivalently, they have the same models.



          This means :




          $text {for every } alpha in Gamma : Sigma vDash alpha$ and $text { for every } beta in Sigma : Gamma vDash beta$.








          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 25 at 19:57









          Mauro ALLEGRANZAMauro ALLEGRANZA

          67.3k449115




          67.3k449115












          • $begingroup$
            Is there any relation with the two expressions in the Q?
            $endgroup$
            – PeptideChain
            Jan 25 at 20:12


















          • $begingroup$
            Is there any relation with the two expressions in the Q?
            $endgroup$
            – PeptideChain
            Jan 25 at 20:12
















          $begingroup$
          Is there any relation with the two expressions in the Q?
          $endgroup$
          – PeptideChain
          Jan 25 at 20:12




          $begingroup$
          Is there any relation with the two expressions in the Q?
          $endgroup$
          – PeptideChain
          Jan 25 at 20:12


















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