Recent content by kompik

  1. K

    Mathim - how to save a session

    It seems that mathim was changed again. When I try to copy the text from mathim, there are no dollar signs, some symbols are copied as unicode symbols, some of them are not copied at all. :-(
  2. K

    Mathim - how to save a session

    Thanks a lot, tommycli! It works nice - the clipboard contains dollars now.
  3. K

    Mathim - how to save a session

    When I type in mathim chat http://mathim.com/ and I try to save all text simply by selecting it, all dollars got lost. Otherwise the TeX markup is kept. I think a possibility of saving it with dollars would be useful, since then I could save the text of chat and process it with TeX. A side...
  4. K

    Ramsey number inequality problem

    http://www.mathdb.org/notes_download/elementary/algebra/ae_A2.pdf
  5. K

    Prove Dual Space Isometry: X = C[0,1] Sup Norm

    As far as I can say, they are. You have \left|\int^1_0 g(t)h(t) dt\right| \le \int^1_0 |g(t)| |h(t)| dt \le \int^1_0 |g(t)| dt therefore ||\varphi_g|| \le \int^1_0 |g(t)| dt . I think that ||\varphi_g|| = \int^1_0 |g(t)| dt holds. A naive approach to show this would be trying to...
  6. K

    How to Calculate Symmetric Relations in Set Theory?

    You can imagine any relation a a table with 7 rows and 7 columns, where you indicate in each position whether the corresponding elements belong to the relation. (This is basically the same as working with the graph of this relation.) A relation is symmetric if and only if this graph/table is...
  7. K

    Proof of Green Theorem in Apostol's Analysis

    Just to save time of potential helpers - the same question was posted in different forums as well and it was answered in mathhelpforum. (I think this should have been done by the OP.) http://groups.google.com/groups/search?q=green+theorem+apostol+kellypedro...
  8. K

    Linear Algebra Problem: Proving det(A) = det(B) for Related Matrices A and B

    Two basic facts you should know (and use them in this exercise): The equality det(A.B)=det(A).det(B) is true for any two nxn matrices. And we have for any invertible matrix det(A^-1)= ? (I think you should be able to guess the result using the definition of the inverse and the...
  9. K

    Legrange->System of equations

    Are you supposed to use Lagrange multipliers? Perhaps the approach minimizing would be good, too. Reformulation: Minimize H(s,t)=(t-s)^2+(t^2-\ln s)^2 for s,t \in \mathbb R and s>0. Differentiating: H_t=2(t-s)+4t(t^2-\ln s)=0 H_s=-2(t-s)-\frac{2(t^2-\ln s)}s=0 Adding these two...
  10. K

    Anticommuting Ring that only has left or right inverse?

    Sorry, my mistake. What I've posted is an example of ring with only one-sided unity :-( I've tried UTFG, here's an example from the book Tsit-Yuen Lam: A First Course in Noncommutative Rings Many rings satisfying some form of "finiteness conditions" can be shown to be Dedekind-finite, but...
  11. K

    Anticommuting Ring that only has left or right inverse?

    What about this http://planetmath.org/encyclopedia/KleinFourRing.html"
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