# Insights Mathematical Quantum Field Theory - Propagators - Comments

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1. Nov 29, 2017

### Urs Schreiber

2. Dec 30, 2017

### A. Neumaier

- ''the the Feynman propagator'' has a the too much.
- The table above Definition 9.2 is unbalanced.
- \widecheck is undefined
- UV divergences are mentioned repeatedly but each time only in passing without any explanation of how it should be related to the wave front set.

3. Jan 2, 2018

### Urs Schreiber

I had a brief comment on this, but have made it more prominent now: new remark 9.27.

I had fixed this before, but apparently it came back with my previous update. The trouble is that I have "widecheck" in my source code for the inverse Fourier transform, but the MathJax here does not seem to know this command. As a hack, I have replaced it by "widetilde", but this is sub-optimal. If you or anyone else reading here has a suggestion for how to typeset this with MathJax, please let me know.

I have fixed this by hand now, but I don't understand why the converter produced this issue in the first place. My source code is correct at this point. So if I forget about fixing this by hand again next time that I make an update, the problem might reappear.

4. Jan 3, 2018

5. Jan 3, 2018

### Urs Schreiber

Thanks! Fixed now.

6. Jan 3, 2018

### vanhees71


7. Jan 3, 2018

### Urs Schreiber

Thanks, that's useful to know. Do you think this gives a way to produce a "widecheck" here on PF?