Exercise 5.3
       
       
         
      
         
           
            1
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            Can 
            the $xj 
            rule be applied in the following cases? If it can, what would the 
            result be? | 
         
         
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          (i) 
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             "x[Fxa®Gx] 
            $zFz 
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          |   | 
          (ii) 
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              [$xFxÚ$yGy] 
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          (iii) 
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            | 
         
         
           
            2
           | 
          Each 
            of the following is a tableau which consists, so far, of just one 
            formula. What rule, if any, can be applied to the formula, and with 
            what result? Note that there is only ever at most one rule which 
            can be applied. 
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          |   | 
          (i) 
             | 
          "x[GxaÙHxa] | 
         
         
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          (ii) | 
          [$xGxa®"yFy] | 
         
         
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          (iii) | 
          ¬[¬$xFx®P] | 
         
         
          |   | 
          (iv) | 
          $x"y[Fx«Ryax] | 
         
         
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          (v) | 
          "x"y"z[[RxaÙRyb]®Sxyz]] | 
         
         
          |   | 
          (vi) | 
          "x"y"z[[RxyÙRyz]®Sxyz]] 
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