Show that $|.|_{1/2}$ is not a norm. [duplicate]












0















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  • $l^p$ not norm, $p<1$

    2 answers




Show that $|.|_{1/2}$ is not a norm. would anybody guide me that how can i prove or disprove?



thanks










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marked as duplicate by Holo, Eric Wofsey, Lee David Chung Lin, ancientmathematician, A. Pongrácz Dec 31 '18 at 8:17


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.




















    0















    This question already has an answer here:




    • $l^p$ not norm, $p<1$

      2 answers




    Show that $|.|_{1/2}$ is not a norm. would anybody guide me that how can i prove or disprove?



    thanks










    share|cite|improve this question













    marked as duplicate by Holo, Eric Wofsey, Lee David Chung Lin, ancientmathematician, A. Pongrácz Dec 31 '18 at 8:17


    This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.


















      0












      0








      0








      This question already has an answer here:




      • $l^p$ not norm, $p<1$

        2 answers




      Show that $|.|_{1/2}$ is not a norm. would anybody guide me that how can i prove or disprove?



      thanks










      share|cite|improve this question














      This question already has an answer here:




      • $l^p$ not norm, $p<1$

        2 answers




      Show that $|.|_{1/2}$ is not a norm. would anybody guide me that how can i prove or disprove?



      thanks





      This question already has an answer here:




      • $l^p$ not norm, $p<1$

        2 answers








      optimization convex-analysis norm nonlinear-optimization regularization






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      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Dec 29 '18 at 1:39









      HumayooHumayoo

      1013




      1013




      marked as duplicate by Holo, Eric Wofsey, Lee David Chung Lin, ancientmathematician, A. Pongrácz Dec 31 '18 at 8:17


      This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.






      marked as duplicate by Holo, Eric Wofsey, Lee David Chung Lin, ancientmathematician, A. Pongrácz Dec 31 '18 at 8:17


      This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
























          1 Answer
          1






          active

          oldest

          votes


















          2














          It doesn't satisfy the triangle inequality. All you need is a counter-example to show it isn't a norm. For example in $mathbb R^2$ consider $(1,0)$ and $(0,1)$.






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          • 1




            Or $(1,4)$ and $(4,1).$ In either this case or yours we have an instance of $|a|+|b|<|a+b|$.
            – DanielWainfleet
            Dec 29 '18 at 6:55


















          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          2














          It doesn't satisfy the triangle inequality. All you need is a counter-example to show it isn't a norm. For example in $mathbb R^2$ consider $(1,0)$ and $(0,1)$.






          share|cite|improve this answer



















          • 1




            Or $(1,4)$ and $(4,1).$ In either this case or yours we have an instance of $|a|+|b|<|a+b|$.
            – DanielWainfleet
            Dec 29 '18 at 6:55
















          2














          It doesn't satisfy the triangle inequality. All you need is a counter-example to show it isn't a norm. For example in $mathbb R^2$ consider $(1,0)$ and $(0,1)$.






          share|cite|improve this answer



















          • 1




            Or $(1,4)$ and $(4,1).$ In either this case or yours we have an instance of $|a|+|b|<|a+b|$.
            – DanielWainfleet
            Dec 29 '18 at 6:55














          2












          2








          2






          It doesn't satisfy the triangle inequality. All you need is a counter-example to show it isn't a norm. For example in $mathbb R^2$ consider $(1,0)$ and $(0,1)$.






          share|cite|improve this answer














          It doesn't satisfy the triangle inequality. All you need is a counter-example to show it isn't a norm. For example in $mathbb R^2$ consider $(1,0)$ and $(0,1)$.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Dec 29 '18 at 3:53

























          answered Dec 29 '18 at 2:02









          FortoxFortox

          607




          607








          • 1




            Or $(1,4)$ and $(4,1).$ In either this case or yours we have an instance of $|a|+|b|<|a+b|$.
            – DanielWainfleet
            Dec 29 '18 at 6:55














          • 1




            Or $(1,4)$ and $(4,1).$ In either this case or yours we have an instance of $|a|+|b|<|a+b|$.
            – DanielWainfleet
            Dec 29 '18 at 6:55








          1




          1




          Or $(1,4)$ and $(4,1).$ In either this case or yours we have an instance of $|a|+|b|<|a+b|$.
          – DanielWainfleet
          Dec 29 '18 at 6:55




          Or $(1,4)$ and $(4,1).$ In either this case or yours we have an instance of $|a|+|b|<|a+b|$.
          – DanielWainfleet
          Dec 29 '18 at 6:55



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