[itex]\vec{v} = v^i\vec{e}_i = g(\vec{v},\vec{e}_i)\vec{e}_i[/itex](adsbygoogle = window.adsbygoogle || []).push({});

The last bit is a sum over i but will need a Ʃ because the Einstein rule only applies to matched superscripts and subscripts and here bot the i are subscripts.

Even if I write out the metric in the basis it doesn't work:

[itex]g(\vec{v},\vec{e}_i)\vec{e}_i=g_{ab}v^ae^{b}_{i} \vec{e}_i[/itex]

In everything else I've ever done the indices have always been where they needed to be for Einstein summation but for some reason in this one they're not. It's no hardship to write the [itex]\Sigma^{n}_{i=1}[/itex] before it but it just feels as though there should be a way to avoid that.

Any suggestions or comments? Thanks very much.

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Why can't I write this in Einstein notation?

Loading...

Similar Threads - can't write Einstein | Date |
---|---|

B Why can't light travel faster than c? | Mar 14, 2018 |

I Can't understand this argument for Lorentz transformation y'=y | Oct 18, 2017 |

I What is the most correct way to write a vector in GR? | Mar 24, 2017 |

I Why can't you use Simultaneity when doing Length Contraction | Jun 30, 2016 |

**Physics Forums - The Fusion of Science and Community**