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  1. Xref: sparky sci.math:10474 sci.physics:13211
  2. Path: sparky!uunet!mcsun!sun4nl!tuegate.tue.nl!blade!johan
  3. From: johan@blade.stack.urc.tue.nl (Johan Wevers)
  4. Newsgroups: sci.math,sci.physics
  5. Subject: Re: tensors
  6. Keywords: Tensor
  7. Message-ID: <5134@tuegate.tue.nl>
  8. Date: 21 Aug 92 08:06:04 GMT
  9. References: <1992Aug20.190041.6215@pellns.alleg.edu> <schlegel.714343318@cwis>
  10. Sender: root@tuegate.tue.nl
  11. Followup-To: sci.math
  12. Organization: MCGV Stack, Eindhoven University of Technology, the Netherlands.
  13. Lines: 18
  14.  
  15. schlegel@cwis.unomaha.edu (Mark Schlegel) writes:
  16.  
  17. [A lot about *matrix* and *vector* calculus]
  18.  
  19. You didn't get the point: as many people, you seem to think that a
  20. tensor is ``something with an index''. That is *NOT TRUE*. Something
  21. is a tensor when it obeys certain transformation rules under
  22. coordinate transformation. For example, the Christoffel symbols
  23. \Gamma^{a}_{bc}, often used in GR, are NO TENSORS. They don't
  24. transform in the right way.
  25.  
  26. ******************************************************************** 
  27. * J.C.A. Wevers                *         u\  _\       /e+        2 * 
  28. * johan@blade.stack.urc.tue.nl *     1 |   \ u \  X  /         |   * 
  29. ******************************** P = - |    >   >---<     + ...|   * 
  30. *     The only nature of       *     N |   /   /     \         |   * 
  31. *     reality is physics       *         u/   /d     u\            *
  32. ********************************************************************
  33.