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The New Coffee Room

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  3. Puzzle time - algebra edition

Puzzle time - algebra edition

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  • bachophileB bachophile

    Link to video

    taiwan_girlT Offline
    taiwan_girlT Offline
    taiwan_girl
    wrote on last edited by
    #3

    @bachophile ๐Ÿ˜† I am glad I am not the only one who did not understand. 555

    George KG 1 Reply Last reply
    • taiwan_girlT taiwan_girl

      @bachophile ๐Ÿ˜† I am glad I am not the only one who did not understand. 555

      George KG Offline
      George KG Offline
      George K
      wrote on last edited by
      #4

      @taiwan_girl said in Puzzle time - algebra edition:

      @bachophile ๐Ÿ˜† I am glad I am not the only one who did not understand. 555

      That makes at least three of us.

      "Now look here, you Baltic gas passer... " - Mik, 6/14/08

      The saying, "Lite is just one damn thing after another," is a gross understatement. The damn things overlap.

      1 Reply Last reply
      • KlausK Offline
        KlausK Offline
        Klaus
        wrote on last edited by
        #5

        Hey, what are you all doing in this thread? I was hoping that the title would scare off math-challenged posters ๐Ÿ˜‰

        1 Reply Last reply
        • jon-nycJ Offline
          jon-nycJ Offline
          jon-nyc
          wrote on last edited by
          #6

          Do the operator mappings have to be unique?

          Only non-witches get due process.

          • Cotton Mather, Salem Massachusetts, 1692
          KlausK 1 Reply Last reply
          • bachophileB Offline
            bachophileB Offline
            bachophile
            wrote on last edited by
            #7

            Jon chimes in to let us know he understands the question.

            Right....tell the truth Klaus, u just made up the word bijection.

            Sounds filthy to me.

            1 Reply Last reply
            • MikM Offline
              MikM Offline
              Mik
              wrote on last edited by
              #8

              Needs pronouns.

              โ€œI am fond of pigs. Dogs look up to us. Cats look down on us. Pigs treat us as equals.โ€ ~Winston S. Churchill

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              • jon-nycJ jon-nyc

                Do the operator mappings have to be unique?

                KlausK Offline
                KlausK Offline
                Klaus
                wrote on last edited by Klaus
                #9

                @jon-nyc said in Puzzle time - algebra edition:

                Do the operator mappings have to be unique?

                I'm not sure what you have in mind, but I mean that, for instance, "+" is interpreted as an operation on sets (for the first task) or logical propositions (for the second task). For instance, you could map "+" to "intersection" (that choice would satisfy equations 1 and 2, but it would be hard to make it work for the other equations, too).

                1 Reply Last reply
                • KlausK Offline
                  KlausK Offline
                  Klaus
                  wrote on last edited by
                  #10

                  Just as a little teaser, this puzzle illustrates the probably most beautiful result of 20th century mathematics/logic. A result that inspired the works of Field medalists and created whole new subfields in mathematics.

                  1 Reply Last reply
                  • jon-nycJ Offline
                    jon-nycJ Offline
                    jon-nyc
                    wrote on last edited by
                    #11

                    Could you map two symbols to the same operator?

                    Only non-witches get due process.

                    • Cotton Mather, Salem Massachusetts, 1692
                    1 Reply Last reply
                    • KlausK Offline
                      KlausK Offline
                      Klaus
                      wrote on last edited by
                      #12

                      Sure.

                      1 Reply Last reply
                      • KlausK Offline
                        KlausK Offline
                        Klaus
                        wrote on last edited by Klaus
                        #13

                        OK, maybe not the right audience here for this kind of puzzle ๐Ÿ™‚

                        Anyway, just for closure, here's a solution:

                        For sets:

                        the operator + is set union
                        ยท is set intersection
                        A^B is the set of functions from B to A
                        1 is any one-element set
                        0 is the empty set
                        2 is any two-element set

                        For logical propositions:

                        the operator + is disjunction
                        ยท is conjunction
                        A^B is the implication B -> A
                        1 is logical truth
                        0 is logical falsity
                        2 is also logical truth (because 2 = 1 + 1 = true OR true = true )

                        As usual for mathematics, I'll leave the verification of the equations from the original post as an exercise to the reader ๐Ÿ™‚ .

                        These mappings form the basis the so-called "Curry-Howard correspondence" and, more recently, "homotopy type theory", an influential modern attempt to "reboot" mathematics.

                        jon-nycJ 1 Reply Last reply
                        • KlausK Klaus

                          OK, maybe not the right audience here for this kind of puzzle ๐Ÿ™‚

                          Anyway, just for closure, here's a solution:

                          For sets:

                          the operator + is set union
                          ยท is set intersection
                          A^B is the set of functions from B to A
                          1 is any one-element set
                          0 is the empty set
                          2 is any two-element set

                          For logical propositions:

                          the operator + is disjunction
                          ยท is conjunction
                          A^B is the implication B -> A
                          1 is logical truth
                          0 is logical falsity
                          2 is also logical truth (because 2 = 1 + 1 = true OR true = true )

                          As usual for mathematics, I'll leave the verification of the equations from the original post as an exercise to the reader ๐Ÿ™‚ .

                          These mappings form the basis the so-called "Curry-Howard correspondence" and, more recently, "homotopy type theory", an influential modern attempt to "reboot" mathematics.

                          jon-nycJ Offline
                          jon-nycJ Offline
                          jon-nyc
                          wrote on last edited by
                          #14

                          @klaus said in Puzzle time - algebra edition:

                          A^B is the implication B -> A

                          I tried that and ruled it out (erroneously) thinking it failed 7

                          Only non-witches get due process.

                          • Cotton Mather, Salem Massachusetts, 1692
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