$f$ is integrable iff the $U(f;P)-L(f;P)< varepsilon$ whenever mesh(P)<$delta$?












0












$begingroup$


This is very close to what is shown in Rudin (Thm 6.6) but Rudin doesn't mention anything about a delta or a mesh in his theorem.



We were supposed to show this in class yesterday but the professor spent more time erasing wrong work than actually proving the theorem. I'm trying to clean up my notes but I want to make sure I'm getting it right.



The statement of the theorem we were given in class:



$f epsilon R[a,b]$ and $f$ is bounded iff $forall varepsilon$ >0, $exists delta$ >0 such that $U(f;P)-L(f;P)< varepsilon$ whenever $mu (P)< delta$.



I don't know how standard the notation is, but $mu (P)$ is the mesh of $P$.



The question is to either:
1) Explain how Rudin's proof is really the same as what we were supposed to do in class even though the statement is different or
2) Explain how to prove this since class was a flop.



Thanks!










share|cite|improve this question









$endgroup$












  • $begingroup$
    Shouldn't the theorem be $f :[a,b] rightarrow mathbb{R}$ bounded is integrable if and only if ... ?
    $endgroup$
    – Digitalis
    Jan 12 at 13:42










  • $begingroup$
    It would also be helpful if you included the theorem 6.6 in your post since we don't all have access to that book.
    $endgroup$
    – Digitalis
    Jan 12 at 13:49
















0












$begingroup$


This is very close to what is shown in Rudin (Thm 6.6) but Rudin doesn't mention anything about a delta or a mesh in his theorem.



We were supposed to show this in class yesterday but the professor spent more time erasing wrong work than actually proving the theorem. I'm trying to clean up my notes but I want to make sure I'm getting it right.



The statement of the theorem we were given in class:



$f epsilon R[a,b]$ and $f$ is bounded iff $forall varepsilon$ >0, $exists delta$ >0 such that $U(f;P)-L(f;P)< varepsilon$ whenever $mu (P)< delta$.



I don't know how standard the notation is, but $mu (P)$ is the mesh of $P$.



The question is to either:
1) Explain how Rudin's proof is really the same as what we were supposed to do in class even though the statement is different or
2) Explain how to prove this since class was a flop.



Thanks!










share|cite|improve this question









$endgroup$












  • $begingroup$
    Shouldn't the theorem be $f :[a,b] rightarrow mathbb{R}$ bounded is integrable if and only if ... ?
    $endgroup$
    – Digitalis
    Jan 12 at 13:42










  • $begingroup$
    It would also be helpful if you included the theorem 6.6 in your post since we don't all have access to that book.
    $endgroup$
    – Digitalis
    Jan 12 at 13:49














0












0








0





$begingroup$


This is very close to what is shown in Rudin (Thm 6.6) but Rudin doesn't mention anything about a delta or a mesh in his theorem.



We were supposed to show this in class yesterday but the professor spent more time erasing wrong work than actually proving the theorem. I'm trying to clean up my notes but I want to make sure I'm getting it right.



The statement of the theorem we were given in class:



$f epsilon R[a,b]$ and $f$ is bounded iff $forall varepsilon$ >0, $exists delta$ >0 such that $U(f;P)-L(f;P)< varepsilon$ whenever $mu (P)< delta$.



I don't know how standard the notation is, but $mu (P)$ is the mesh of $P$.



The question is to either:
1) Explain how Rudin's proof is really the same as what we were supposed to do in class even though the statement is different or
2) Explain how to prove this since class was a flop.



Thanks!










share|cite|improve this question









$endgroup$




This is very close to what is shown in Rudin (Thm 6.6) but Rudin doesn't mention anything about a delta or a mesh in his theorem.



We were supposed to show this in class yesterday but the professor spent more time erasing wrong work than actually proving the theorem. I'm trying to clean up my notes but I want to make sure I'm getting it right.



The statement of the theorem we were given in class:



$f epsilon R[a,b]$ and $f$ is bounded iff $forall varepsilon$ >0, $exists delta$ >0 such that $U(f;P)-L(f;P)< varepsilon$ whenever $mu (P)< delta$.



I don't know how standard the notation is, but $mu (P)$ is the mesh of $P$.



The question is to either:
1) Explain how Rudin's proof is really the same as what we were supposed to do in class even though the statement is different or
2) Explain how to prove this since class was a flop.



Thanks!







real-analysis integration partitions-for-integration






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 12 at 12:56









TheLonelyGodWithABoxTheLonelyGodWithABox

193




193












  • $begingroup$
    Shouldn't the theorem be $f :[a,b] rightarrow mathbb{R}$ bounded is integrable if and only if ... ?
    $endgroup$
    – Digitalis
    Jan 12 at 13:42










  • $begingroup$
    It would also be helpful if you included the theorem 6.6 in your post since we don't all have access to that book.
    $endgroup$
    – Digitalis
    Jan 12 at 13:49


















  • $begingroup$
    Shouldn't the theorem be $f :[a,b] rightarrow mathbb{R}$ bounded is integrable if and only if ... ?
    $endgroup$
    – Digitalis
    Jan 12 at 13:42










  • $begingroup$
    It would also be helpful if you included the theorem 6.6 in your post since we don't all have access to that book.
    $endgroup$
    – Digitalis
    Jan 12 at 13:49
















$begingroup$
Shouldn't the theorem be $f :[a,b] rightarrow mathbb{R}$ bounded is integrable if and only if ... ?
$endgroup$
– Digitalis
Jan 12 at 13:42




$begingroup$
Shouldn't the theorem be $f :[a,b] rightarrow mathbb{R}$ bounded is integrable if and only if ... ?
$endgroup$
– Digitalis
Jan 12 at 13:42












$begingroup$
It would also be helpful if you included the theorem 6.6 in your post since we don't all have access to that book.
$endgroup$
– Digitalis
Jan 12 at 13:49




$begingroup$
It would also be helpful if you included the theorem 6.6 in your post since we don't all have access to that book.
$endgroup$
– Digitalis
Jan 12 at 13:49










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