JOSS paper ambiguous use of mathematical symbol for Mueller matrix and depolarizer

[arendMoerman]

This issue is part of my JOSS review: https://github.com/openjournals/joss-reviews/issues/7375

In the paper, there is one mathematical equation describing the formalism of the Mueller matrix decomposition, where the full matrix $$M$$ is decomposed into a depolarizer, diattenuator, and retarder: $$M=M M\mathrm{R} M\mathrm{D}.$$ As it is now, the symbol $$M$$ is used for both the total matrix and the depolarizer constituent of the decomposition, which is ambiguous.

I believe this to be just a typo in the paper however, as in the online documentation the symbol $$M_\Delta$$ is used for the depolarizer, which would break the ambiguity and resolve this issue.

Could you please fix this in the JOSS paper please?

[Jashcraf]

Thank you for the catch! I think it may be a compilation issue? The $M_{\Delta}$ is present in paper.md

https://github.com/Jashcraf/katsu/blob/e294475e7c70c3f8460712946965c2c374eb829e/paper.md?plain=1#L57

And shows up in the markdown preview

Looking at the Github action I found the source of the error

[INFO] [makePDF] LaTeX run number 1
Latexmk: ====Undefined refs and citations with line #s in .tex file:
Missing character: There is no 𝛥 (U+1D6E5) in font [NewCM10-Bold.otf]:mode=ba
Missing character: There is no 𝛥 (U+1D6E5) in font [NewCM10-Bold.otf]:mode=base;script=latn;language=dflt;!
Missing character: There is no 𝛥 (U+1D6E5) in font [NewCM10-Bold.otf]:mode=ba
Missing character: There is no 𝛥 (U+1D6E5) in font [NewCM10-Bold.otf]:mode=base;script=latn;language=dflt;!
Missing character: There is no 𝛥 (U+1D6E5) in font [NewCM10-Bold.otf]:mode=ba
Missing character: There is no 𝛥 (U+1D6E5) in font [NewCM10-Bold.otf]:mode=base;script=latn;language=dflt;!
Missing character: There is no 𝛥 (U+1D6E5) in font [NewCM10-Bold.otf]:mode=ba

It may not be present because the Delta is inside the \mathbf{*}, I'll move the Delta outside to see if that fixes it.

[Jashcraf]

Looks like it worked!

[arendMoerman]

Great!