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FeynCalc / feyncalc

Mathematica package for algebraic calculations in elementary particle physics.
https://feyncalc.github.io
GNU General Public License v3.0
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Cyclicity of the color trace #224

Closed NefedovM closed 1 year ago

NefedovM commented 1 year ago

Hi, everyone evaluating

SUNSimplify[SUNTrace[SUNT[a, a, b, b]]] // InputForm

I get

SUNTrace[SUNT[SUNIndex[FCGV["sun16131"]]] . SUNT[SUNIndex[FCGV["sun16131"]]] . SUNT[SUNIndex[FCGV["sun16132"]]] . SUNT[SUNIndex[FCGV["sun16132"]]]]

while evaluating an equivalent expression

SUNSimplify[SUNTrace[SUNT[a, b, b, a]]] // InputForm

I get

CA*CF^2

as it should be.

So the cyclic property of the color trace doesn't seem to always work. Is it a known issue?

M.N.

vsht commented 1 year ago

Hi Maxim,

many thanks for the bug report. I'll upload the fix tomorrow, but for the moment you can just use the option SUNTraceEvaluate->True, which is set to Automatic by default.

Am 20. Juni 2023 16:12:25 UTC schrieb NefedovM @.***>:

  • Your Mathematica version

    13.0.1 for Linux x86 (64-bit) (January 29, 2022)

  • Your FeynCalc version

    "10.0.0" (development)

  • Did you try to reinstall FeynCalc (stable version) using the automatic installer to make sure that you have the latest bugfixes?

    No, should I?

Hi, everyone evaluating

SUNSimplify[SUNTrace[SUNT[a, a, b, b]]] // InputForm

I get

SUNTrace[SUNT[SUNIndex[FCGV["sun16131"]]] . SUNT[SUNIndex[FCGV["sun16131"]]] . SUNT[SUNIndex[FCGV["sun16132"]]] . SUNT[SUNIndex[FCGV["sun16132"]]]]

while evaluating an equivalent expression

SUNSimplify[SUNTrace[SUNT[a, b, b, a]]] // InputForm

I get

CA*CF^2

as it should be.

So the cyclic property of the color trace doesn't seem to always work. Is it a known issue?

M.N.

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vsht commented 1 year ago

The issue should be now fixed, feel free to reopen if there are still remaining problems.