# Homework Help: Quantum Theory, propagator and causality, commutator

1. Jul 19, 2017

### binbagsss

1. The problem statement, all variables and given/known data

Question:

To find/ explain why there exists a continous lorentz transformation that flips the sign for space-like seperation but not time-like.

2. Relevant equations

Signature $(-,+,+...)$

Definition of lorentz transformation:

$x^u=\lambda^u_v x^v$
$\eta_{uv}\lambda^u_p\lambda^v_{\sigma} = \eta_{p\sigma}$

3. The attempt at a solution

$\Delta \eta_{uv} y^v x^u < 0$ for time-like seperation
$\Delta \eta_{uv} y^v x^u > 0$ for space-like seperation

And I dont really know where to get started.

Many thanks

2. Jul 24, 2017

### PF_Help_Bot

Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.