• Einstein notation

    From Douglas Dana Edward^2 Parker-Goncz@21:1/5 to All on Mon Mar 30 22:39:21 2020
    Hello and good morning physicists.

    Usin Google Groups:

    "
    Results for "Einstein notation" in sci.physics.research
    Results: about 0 for "Einstein notation"
    No results found
    "

    How odd.

    I would think the Einstein notation, for the identity matrix at
    least, would be in the 10th grade American algebra and functions
    curriculum if not a lower grade's.

    Douglas "Doofus Einstein" Goncz
    Replikon Research FCN 783774974

    [[Mod. note -- I fear the author is quite over-optimistic about the
    level of mathematical sophistication in American (or Canadian, for
    that matter) 10th grade algebra curricula.

    Einstein notation (https://en.wikipedia.org/wiki/Einstein_notation),
    a.k.a., the Einstein summation convention, is not generally introduced
    in math or physics curricula until it's introduced as part of tensor
    calculus, which is often only an optional course taken late in a 3-
    or 4-year university degree.

    There has been a recent movement introducing general relativity in
    such courses/degrees -- see, e.g.,
    Christensen & Moore, /Physics Today/ 65(6), 41 (2012),
    http://dx.doi.org/10.1063/PT.3.1605

    Such courses typically include an elementary treatment of tensor
    calculus, including the use of the Einstein summation convention.
    The book
    James B Hartle
    "Gravity: AN Introduction to Einstein's General Relativity"
    Addison-Wesley, 2003, ISBN-10 0-8053-8662-9
    is a class & widely-priased textbook for such courses.
    -- jt]]

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Michael Cole@21:1/5 to All on Thu Apr 23 12:07:10 2020
    On Tuesday, March 31, 2020 at 1:39:24 AM UTC-4, Douglas Dana Edward^2 Parker-Goncz (fully) wrote:
    Hello and good morning physicists.

    Usin Google Groups:

    "
    Results for "Einstein notation" in sci.physics.research
    Results: about 0 for "Einstein notation"
    No results found
    "

    How odd.

    I would think the Einstein notation, for the identity matrix at
    least, would be in the 10th grade American algebra and functions
    curriculum if not a lower grade's.

    Douglas "Doofus Einstein" Goncz
    Replikon Research FCN 783774974

    [[Mod. note -- I fear the author is quite over-optimistic about the
    level of mathematical sophistication in American (or Canadian, for
    that matter) 10th grade algebra curricula.

    Einstein notation (https://en.wikipedia.org/wiki/Einstein_notation),
    a.k.a., the Einstein summation convention, is not generally introduced
    in math or physics curricula until it's introduced as part of tensor calculus, which is often only an optional course taken late in a 3-
    or 4-year university degree.

    There has been a recent movement introducing general relativity in
    such courses/degrees -- see, e.g.,
    Christensen & Moore, /Physics Today/ 65(6), 41 (2012),
    http://dx.doi.org/10.1063/PT.3.1605

    Such courses typically include an elementary treatment of tensor
    calculus, including the use of the Einstein summation convention.
    The book
    James B Hartle
    "Gravity: AN Introduction to Einstein's General Relativity"
    Addison-Wesley, 2003, ISBN-10 0-8053-8662-9
    is a class & widely-priased textbook for such courses.
    -- jt]]

    [Moderator's note: I guess that Jonathan means "classic and widely
    praised textbook". -P.H.]

    I've never understood why we don't teach Einstein notation to
    undergraduate math majors taking Linear Algebra. Many basic facts about matrices are easy to prove using the notation. For example, basic facts
    about determinants (e.g. multiplicativity and the equivalence between nonvanishing of the determinant and invertibility of the matrix) are
    effortless to prove if one introduces the antisymmetric epsilon symbol
    and writes the definition of the determinant that way.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jos Bergervoet@21:1/5 to Michael Cole on Sat Apr 25 20:43:44 2020
    On 20/04/23 1:07 PM, Michael Cole wrote:
    On Tuesday, March 31, 2020 at 1:39:24 AM UTC-4, Douglas Dana Edward^2 Parker-Goncz (fully) wrote:
    ...
    ...
    Einstein notation (https://en.wikipedia.org/wiki/Einstein_notation),
    a.k.a., the Einstein summation convention, is not generally introduced
    in math or physics curricula until it's introduced as part of tensor
    calculus, which is often only an optional course taken late in a 3-
    or 4-year university degree.

    There has been a recent movement introducing general relativity in
    such courses/degrees -- see, e.g.,
    Christensen & Moore, /Physics Today/ 65(6), 41 (2012),
    http://dx.doi.org/10.1063/PT.3.1605

    Such courses typically include an elementary treatment of tensor
    calculus, including the use of the Einstein summation convention.
    The book
    James B Hartle
    "Gravity: AN Introduction to Einstein's General Relativity"
    Addison-Wesley, 2003, ISBN-10 0-8053-8662-9
    is a class & widely-priased textbook for such courses.
    -- jt]]

    [Moderator's note: I guess that Jonathan means "classic and widely
    praised textbook". -P.H.]

    I've never understood why we don't teach Einstein notation to
    undergraduate math majors taking Linear Algebra.

    But maybe to do it right at once, we should then teach them using the differential forms notation. Then Einstein's theories are expressed even
    easier (and Maxwell's as well). Although perhaps not everyone agrees..

    <https://www.quora.com/Is-general-relativity-ever-done-in-terms-of-differential-forms-and-exterior-calculus-or-is-it-exclusively-done-using-tensors-and-index-notation>

    <https://physics.stackexchange.com/questions/91867/general-relativity-in-terms-of-differential-forms>

    <https://physics.stackexchange.com/questions/487976/is-there-differential-form-notation-for-maxwells-equation-in-curved-spacetime>

    ... Many basic facts about
    matrices are easy to prove using the notation. For example, basic facts about determinants (e.g. multiplicativity and the equivalence between nonvanishing of the determinant and invertibility of the matrix) are effortless to prove if one introduces the antisymmetric epsilon symbol
    and writes the definition of the determinant that way.

    Well, those things that follow from coordinate independence would
    certainly be obvious (but even more so when using differential forms
    and exterior derivatives). For proofs where more is needed, we may
    still need to really understand what it all means! :-)

    --
    Jos

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