Crthuky

1. Sharing float (fig) and thm counter can be done with newtheoremtheorem[figure]Theorem.


2. Correctly ordering float (fig) counter based on actual location in the PDF (as opposed to location in source code) can be done with MakeSortedfigure from perpage.sty.


3. Sharing float (fig) and eqn counter can be done with makeatletterletc@equationc@figuremakeatother.

I can do 1 and 2 together (see mwe-b).
I can do 1 and 3 together (see mwe-c).
But I can't do all three together (see mwe-d).

Partial/fake solution. I can skirt the issue by making a myeqn environment (see mwe-a).

Question. Is there an actual solution that allows you to keep the equation environment? Maybe one can resolve the clash in mwe-d by swapping c@figure out for something (based on the precise implementation of perpage.sty)? Any help would be greatly appreciated!

%% MWE-A
documentlassarticle
usepackageblindtext
newtheoremtheorem[figure]Theorem %1
usepackageperpageMakeSortedfigure %2
newenvironmentmyeqn
 stepcounterfigurehfillbeginmath
 endmathhfill(arabicfigure)
begindocument
begintheoremblindtextendtheorem
beginfigureblindtextcaptionCaptionendfigure
beginmyeqna^2+b^2=c^2endmyeqn
enddocument

%% MWE-B
documentclassarticle
usepackageblindtext
newtheoremtheorem[figure]Theorem %1
usepackageperpageMakeSortedfigure %2
begindocument
begintheoremblindtextendtheorem
beginfigureblindtextcaptionCaptionendfigure
beginequationa^2+b^2=c^2endequation
enddocument

%% MWE-C
documentclassarticle
usepackageblindtext
newtheoremtheorem[figure]Theorem %1
makeatletterletc@equationc@figuremakeatother %3
begindocument
begintheoremblindtextendtheorem
beginfigureblindtextcaptionCaptionendfigure
beginequationa^2+b^2=c^2endequation
enddocument

%% MWE-D
documentclassarticle
usepackageblindtext
newtheoremtheorem[figure]Theorem %1
usepackageperpageMakeSortedfigure %2
makeatletterletc@equationc@figuremakeatother %3
begindocument
begintheoremblindtextendtheorem
beginfigureblindtextcaptionCaptionendfigure
beginequationa^2+b^2=c^2endequation
enddocument