What does the notation inf… mean?

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$$infk : f in C^k$$



What does $infcdot$ mean? I have been looking, but haven't found anything.







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  • 3




    It means infimum.
    – Raskolnikov
    Jul 21 at 11:16






  • 2




    It doesn't make a lot of sense in this particular context, since if $f$ is $mathcal C^k$ for any one $k$, then it is also $mathcal C^0$, so this infimum is either $0$ or (perhaps) $infty$.
    – Henning Makholm
    Jul 21 at 11:23














up vote
0
down vote

favorite












I came across



$$infk : f in C^k$$



What does $infcdot$ mean? I have been looking, but haven't found anything.







share|cite|improve this question

















  • 3




    It means infimum.
    – Raskolnikov
    Jul 21 at 11:16






  • 2




    It doesn't make a lot of sense in this particular context, since if $f$ is $mathcal C^k$ for any one $k$, then it is also $mathcal C^0$, so this infimum is either $0$ or (perhaps) $infty$.
    – Henning Makholm
    Jul 21 at 11:23












up vote
0
down vote

favorite









up vote
0
down vote

favorite











I came across



$$infk : f in C^k$$



What does $infcdot$ mean? I have been looking, but haven't found anything.







share|cite|improve this question













I came across



$$infk : f in C^k$$



What does $infcdot$ mean? I have been looking, but haven't found anything.









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Jul 21 at 11:26









Rodrigo de Azevedo

12.6k41751




12.6k41751









asked Jul 21 at 11:15









Filip

336




336







  • 3




    It means infimum.
    – Raskolnikov
    Jul 21 at 11:16






  • 2




    It doesn't make a lot of sense in this particular context, since if $f$ is $mathcal C^k$ for any one $k$, then it is also $mathcal C^0$, so this infimum is either $0$ or (perhaps) $infty$.
    – Henning Makholm
    Jul 21 at 11:23












  • 3




    It means infimum.
    – Raskolnikov
    Jul 21 at 11:16






  • 2




    It doesn't make a lot of sense in this particular context, since if $f$ is $mathcal C^k$ for any one $k$, then it is also $mathcal C^0$, so this infimum is either $0$ or (perhaps) $infty$.
    – Henning Makholm
    Jul 21 at 11:23







3




3




It means infimum.
– Raskolnikov
Jul 21 at 11:16




It means infimum.
– Raskolnikov
Jul 21 at 11:16




2




2




It doesn't make a lot of sense in this particular context, since if $f$ is $mathcal C^k$ for any one $k$, then it is also $mathcal C^0$, so this infimum is either $0$ or (perhaps) $infty$.
– Henning Makholm
Jul 21 at 11:23




It doesn't make a lot of sense in this particular context, since if $f$ is $mathcal C^k$ for any one $k$, then it is also $mathcal C^0$, so this infimum is either $0$ or (perhaps) $infty$.
– Henning Makholm
Jul 21 at 11:23










3 Answers
3






active

oldest

votes

















up vote
3
down vote



accepted










It means infimum. So, $infldots$ is the infimum of the set $ldots$ (assuming that it is a non-empty set of real numbers with a lower bound).






share|cite|improve this answer





















  • To save a google search: en.m.wikipedia.org/wiki/Infimum_and_supremum
    – Crosby
    Jul 21 at 11:19

















up vote
4
down vote













Suppose that you have a non-empty set of numbers,as an example $A = 1,10,pi,55, 11.2, sqrt2, 1over 2$ then the infimum of this set is the greatest lower bound of the set. In this simple case $$infA=1over 2$$



As an added bonus: what you gave us $$infk: fin C^k$$ means that, given a function $f$ differentiable $n$ times, the infimum is the lower possible $k$ such that the $k$-th derivative of this function is continuous. But I think that $k$ will be $0$ every time..






share|cite|improve this answer



















  • 1




    "lower upper bound"??
    – Henning Makholm
    Jul 21 at 11:24










  • Oops, my bad, I'm correcting it
    – Davide Morgante
    Jul 21 at 11:24






  • 2




    Maybe you meant not "infinium" but "infimum" and not "lower bound" but "greatest lower bound"
    – Ð®Ñ€Ñ–й Ярош
    Jul 21 at 11:35










  • Thank you all, I wrote the answer quickly! Now it's all corrected
    – Davide Morgante
    Jul 21 at 11:37






  • 1




    And by axiom, every non empty down bounded set of real numbers has infimum...
    – dmtri
    Jul 21 at 12:17

















up vote
3
down vote













Lower bound of some set of numbers is number which smaller or equal to any number of the set.

Greatest lower bound of some set of numbers is a number which is a lower bound of the set and is bigger or equal to any other lower bound of the set. $inf A$ means greatest lower bound of the set $A$. So e.g. $inf A = 5$ means greatest lower bound of the set $A$ is $5$.
Greatest lower bound is also called infimum.






share|cite|improve this answer





















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    3 Answers
    3






    active

    oldest

    votes








    3 Answers
    3






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    3
    down vote



    accepted










    It means infimum. So, $infldots$ is the infimum of the set $ldots$ (assuming that it is a non-empty set of real numbers with a lower bound).






    share|cite|improve this answer





















    • To save a google search: en.m.wikipedia.org/wiki/Infimum_and_supremum
      – Crosby
      Jul 21 at 11:19














    up vote
    3
    down vote



    accepted










    It means infimum. So, $infldots$ is the infimum of the set $ldots$ (assuming that it is a non-empty set of real numbers with a lower bound).






    share|cite|improve this answer





















    • To save a google search: en.m.wikipedia.org/wiki/Infimum_and_supremum
      – Crosby
      Jul 21 at 11:19












    up vote
    3
    down vote



    accepted







    up vote
    3
    down vote



    accepted






    It means infimum. So, $infldots$ is the infimum of the set $ldots$ (assuming that it is a non-empty set of real numbers with a lower bound).






    share|cite|improve this answer













    It means infimum. So, $infldots$ is the infimum of the set $ldots$ (assuming that it is a non-empty set of real numbers with a lower bound).







    share|cite|improve this answer













    share|cite|improve this answer



    share|cite|improve this answer











    answered Jul 21 at 11:18









    José Carlos Santos

    114k1698177




    114k1698177











    • To save a google search: en.m.wikipedia.org/wiki/Infimum_and_supremum
      – Crosby
      Jul 21 at 11:19
















    • To save a google search: en.m.wikipedia.org/wiki/Infimum_and_supremum
      – Crosby
      Jul 21 at 11:19















    To save a google search: en.m.wikipedia.org/wiki/Infimum_and_supremum
    – Crosby
    Jul 21 at 11:19




    To save a google search: en.m.wikipedia.org/wiki/Infimum_and_supremum
    – Crosby
    Jul 21 at 11:19










    up vote
    4
    down vote













    Suppose that you have a non-empty set of numbers,as an example $A = 1,10,pi,55, 11.2, sqrt2, 1over 2$ then the infimum of this set is the greatest lower bound of the set. In this simple case $$infA=1over 2$$



    As an added bonus: what you gave us $$infk: fin C^k$$ means that, given a function $f$ differentiable $n$ times, the infimum is the lower possible $k$ such that the $k$-th derivative of this function is continuous. But I think that $k$ will be $0$ every time..






    share|cite|improve this answer



















    • 1




      "lower upper bound"??
      – Henning Makholm
      Jul 21 at 11:24










    • Oops, my bad, I'm correcting it
      – Davide Morgante
      Jul 21 at 11:24






    • 2




      Maybe you meant not "infinium" but "infimum" and not "lower bound" but "greatest lower bound"
      – Ð®Ñ€Ñ–й Ярош
      Jul 21 at 11:35










    • Thank you all, I wrote the answer quickly! Now it's all corrected
      – Davide Morgante
      Jul 21 at 11:37






    • 1




      And by axiom, every non empty down bounded set of real numbers has infimum...
      – dmtri
      Jul 21 at 12:17














    up vote
    4
    down vote













    Suppose that you have a non-empty set of numbers,as an example $A = 1,10,pi,55, 11.2, sqrt2, 1over 2$ then the infimum of this set is the greatest lower bound of the set. In this simple case $$infA=1over 2$$



    As an added bonus: what you gave us $$infk: fin C^k$$ means that, given a function $f$ differentiable $n$ times, the infimum is the lower possible $k$ such that the $k$-th derivative of this function is continuous. But I think that $k$ will be $0$ every time..






    share|cite|improve this answer



















    • 1




      "lower upper bound"??
      – Henning Makholm
      Jul 21 at 11:24










    • Oops, my bad, I'm correcting it
      – Davide Morgante
      Jul 21 at 11:24






    • 2




      Maybe you meant not "infinium" but "infimum" and not "lower bound" but "greatest lower bound"
      – Ð®Ñ€Ñ–й Ярош
      Jul 21 at 11:35










    • Thank you all, I wrote the answer quickly! Now it's all corrected
      – Davide Morgante
      Jul 21 at 11:37






    • 1




      And by axiom, every non empty down bounded set of real numbers has infimum...
      – dmtri
      Jul 21 at 12:17












    up vote
    4
    down vote










    up vote
    4
    down vote









    Suppose that you have a non-empty set of numbers,as an example $A = 1,10,pi,55, 11.2, sqrt2, 1over 2$ then the infimum of this set is the greatest lower bound of the set. In this simple case $$infA=1over 2$$



    As an added bonus: what you gave us $$infk: fin C^k$$ means that, given a function $f$ differentiable $n$ times, the infimum is the lower possible $k$ such that the $k$-th derivative of this function is continuous. But I think that $k$ will be $0$ every time..






    share|cite|improve this answer















    Suppose that you have a non-empty set of numbers,as an example $A = 1,10,pi,55, 11.2, sqrt2, 1over 2$ then the infimum of this set is the greatest lower bound of the set. In this simple case $$infA=1over 2$$



    As an added bonus: what you gave us $$infk: fin C^k$$ means that, given a function $f$ differentiable $n$ times, the infimum is the lower possible $k$ such that the $k$-th derivative of this function is continuous. But I think that $k$ will be $0$ every time..







    share|cite|improve this answer















    share|cite|improve this answer



    share|cite|improve this answer








    edited Jul 21 at 12:18


























    answered Jul 21 at 11:22









    Davide Morgante

    1,812220




    1,812220







    • 1




      "lower upper bound"??
      – Henning Makholm
      Jul 21 at 11:24










    • Oops, my bad, I'm correcting it
      – Davide Morgante
      Jul 21 at 11:24






    • 2




      Maybe you meant not "infinium" but "infimum" and not "lower bound" but "greatest lower bound"
      – Ð®Ñ€Ñ–й Ярош
      Jul 21 at 11:35










    • Thank you all, I wrote the answer quickly! Now it's all corrected
      – Davide Morgante
      Jul 21 at 11:37






    • 1




      And by axiom, every non empty down bounded set of real numbers has infimum...
      – dmtri
      Jul 21 at 12:17












    • 1




      "lower upper bound"??
      – Henning Makholm
      Jul 21 at 11:24










    • Oops, my bad, I'm correcting it
      – Davide Morgante
      Jul 21 at 11:24






    • 2




      Maybe you meant not "infinium" but "infimum" and not "lower bound" but "greatest lower bound"
      – Ð®Ñ€Ñ–й Ярош
      Jul 21 at 11:35










    • Thank you all, I wrote the answer quickly! Now it's all corrected
      – Davide Morgante
      Jul 21 at 11:37






    • 1




      And by axiom, every non empty down bounded set of real numbers has infimum...
      – dmtri
      Jul 21 at 12:17







    1




    1




    "lower upper bound"??
    – Henning Makholm
    Jul 21 at 11:24




    "lower upper bound"??
    – Henning Makholm
    Jul 21 at 11:24












    Oops, my bad, I'm correcting it
    – Davide Morgante
    Jul 21 at 11:24




    Oops, my bad, I'm correcting it
    – Davide Morgante
    Jul 21 at 11:24




    2




    2




    Maybe you meant not "infinium" but "infimum" and not "lower bound" but "greatest lower bound"
    – Ð®Ñ€Ñ–й Ярош
    Jul 21 at 11:35




    Maybe you meant not "infinium" but "infimum" and not "lower bound" but "greatest lower bound"
    – Ð®Ñ€Ñ–й Ярош
    Jul 21 at 11:35












    Thank you all, I wrote the answer quickly! Now it's all corrected
    – Davide Morgante
    Jul 21 at 11:37




    Thank you all, I wrote the answer quickly! Now it's all corrected
    – Davide Morgante
    Jul 21 at 11:37




    1




    1




    And by axiom, every non empty down bounded set of real numbers has infimum...
    – dmtri
    Jul 21 at 12:17




    And by axiom, every non empty down bounded set of real numbers has infimum...
    – dmtri
    Jul 21 at 12:17










    up vote
    3
    down vote













    Lower bound of some set of numbers is number which smaller or equal to any number of the set.

    Greatest lower bound of some set of numbers is a number which is a lower bound of the set and is bigger or equal to any other lower bound of the set. $inf A$ means greatest lower bound of the set $A$. So e.g. $inf A = 5$ means greatest lower bound of the set $A$ is $5$.
    Greatest lower bound is also called infimum.






    share|cite|improve this answer

























      up vote
      3
      down vote













      Lower bound of some set of numbers is number which smaller or equal to any number of the set.

      Greatest lower bound of some set of numbers is a number which is a lower bound of the set and is bigger or equal to any other lower bound of the set. $inf A$ means greatest lower bound of the set $A$. So e.g. $inf A = 5$ means greatest lower bound of the set $A$ is $5$.
      Greatest lower bound is also called infimum.






      share|cite|improve this answer























        up vote
        3
        down vote










        up vote
        3
        down vote









        Lower bound of some set of numbers is number which smaller or equal to any number of the set.

        Greatest lower bound of some set of numbers is a number which is a lower bound of the set and is bigger or equal to any other lower bound of the set. $inf A$ means greatest lower bound of the set $A$. So e.g. $inf A = 5$ means greatest lower bound of the set $A$ is $5$.
        Greatest lower bound is also called infimum.






        share|cite|improve this answer













        Lower bound of some set of numbers is number which smaller or equal to any number of the set.

        Greatest lower bound of some set of numbers is a number which is a lower bound of the set and is bigger or equal to any other lower bound of the set. $inf A$ means greatest lower bound of the set $A$. So e.g. $inf A = 5$ means greatest lower bound of the set $A$ is $5$.
        Greatest lower bound is also called infimum.







        share|cite|improve this answer













        share|cite|improve this answer



        share|cite|improve this answer











        answered Jul 21 at 11:30









        Юрій Ярош

        993513




        993513






















             

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