Recent content by explain

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    Exact Arithmetic using Continued Fractions

    There are already some implementations of Gosper's algorithms. For example here: http://contfrac.sourceforge.net/ What are the problems with Gosper's algorithms that you are primarily trying to solve? Also, which programming language are you using? Just curious.
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    Exact Arithmetic using Continued Fractions

    Did you look at the work of Potts, Edalat, and others on LCF and Moebius-based methods? I wonder how your approach connects with those.
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    Exact Arithmetic using Continued Fractions

    I'm not sure you can guarantee termination in cases such as computing f(g(x)) where x is integer and f(g(x)) is also integer, but g(x) is transcendental... There seems to be a conclusion in the literature that CF-based methods are slower than other methods for exact arithmetic. If you have...
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    Understanding Exterior Products of Multiple Vectors

    a new free e-book about linear algebra using exterior products; explains all about determinants and also Pfaffians, gives specific examples of calculations. http://homepages.physik.uni-muenchen.de/~winitzki/Linear_algebra_exterior.pdf
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    Nobody complains about physicists' math?

    hello, jostpuur. You seem to be interested in the lack of rigorous mathematics in physics. I am trying to show examples where physicists proceed regardless of nonrigorous mathematics. The examples I showed are not simply mistakes in calculations but mistakes that originated from lack of...
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    Nobody complains about physicists' math?

    What you are saying is that an approximation is used beyond the range of its validity, just because a more precise computation is too complicated. This is a different story. What I meant to say is that the "black magic" of renormalization is not even presented as anything different from the...
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    Nobody complains about physicists' math?

    Then I would give the example of renormalization in quantum field theory. It is an accepted standard practice to perform renormalization using totally unjustified mathematical steps (Feynman integral, perturbative expansion, cutoffs, counterterms, etc.). These unjustified mathematical steps are...
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    Nobody complains about physicists' math?

    Somebody asked whether there are actual examples when insufficient knowledge of mathematics gave wrong results in physics. There certainly exist many examples where physicists have arrived to incorrect conclusions due to wrong understanding of some mathematical issues. However, these examples...
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    Introduction to Quantum Field Theory in curved spacetime

    I think Birrell-Davies is pretty much unreadable for a beginning graduate student. If you already have a PhD and have working knowledge of quantum field theory then you can understand Birrell-Davies with considerable effort. In my view this is the case with almost any advanced monograph. Another...
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    How to Find the Inverse of a 4th Order Tensor in the Isotropic Case

    titous The problem is that people here have no clue what is a "global 2nd order field" or "B:E" or "alpha * K". People here know standard mathematics, but you are using mathematical terminology that is highly nonstandard (although maybe everyone in your field uses it). So you won't be able to...
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    Building Invariants from Vector, Levi-Civita Symbol

    The LaTeX is entered as [ tex ] \ alpha [ / tex ] (remove spaces). I think you are trying to invent a generalization of spinors. A spinor changes sign when you rotate by 2\pi. But a spinor is not multiplied by \exp(\imath \pi/2) under rotation by \pi. And also inversion just leaves a spinor...
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    A good book in Differential Geometry FOR GR?

    I felt that this was a bit offensive, - don't you think? Especially considering that most GR books do things this way. For example, Landau&Lifschitz Classical theory of fields.
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    A good book in Differential Geometry FOR GR?

    smallphi try this set of lecture notes (I already posted a link in another thread), maybe you will like it better. http://www.theorie.physik.uni-muenchen.de/~serge/T7/ I would also agree with Chris Hillman's comment about your expectations being too high. The kind of book you are looking for...
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    Exploring the Function and Applications of Lie Derivative

    I think it's quite possible to avoid "physical arguments" when dealing with pure mathematics. A student just needs to understand why a new notion is being introduced. For example, in functional analysis: one is supposed to learn a large number of definitions; an operator can be closed...
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    What is the point of Newton's First Law?

    The second law is the most useful for calculations, but the other two laws are needed conceptually. Here is an interpretation of Newton's laws: First law: There exist "objects not acted upon by outside forces", i.e. isolated bodies very far from all other bodies. Also, there exist reference...
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