On Fri, Nov 22, 2013 at 2:33 PM, F. B. <[email protected]> wrote: > Hi, I was recently facing a problem in Newtonian mechanics vs. special > relativity: textbooks represent Newtonian objects as 1-offset > vector/matrices/tensors, while in special relativity they are 0-offset ones, > by the addition of a time-like dimension. > > I was drafting on my IPython notebook some ways to make classical mechanics > work along with special relativity, and this problem seems to be an issue, > unless it simply gets ignored by breaking compatibility with textbooks and > by shifting indices when passing from classical to relativistic mechanics. > > Do you think that an offset on index-counting for vectors/matrices/tensors > could be a good idea?
For sure we should allow indexing from 1 or from 0, depending on the physical and mathematical context. This is related to this: https://plus.google.com/u/0/+Ond%C5%99ej%C4%8Cert%C3%ADk/posts/8FKW6vyuKsy and your example of i=1, 2, 3 (classical mechanics) vs mu=0, 1, 2, 3 (special/general relativity/QFT) is a great one. Ondrej P.S. I've seen also the mu=1, 2, 3, 4 usage in some older textbooks, where 1, 2, 3 is the same as in classical mechanics and 4th is the time. But I would not encourage this usage and rather follow the usual modern physics notation. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. For more options, visit https://groups.google.com/groups/opt_out.
