Originally Posted by

**beanbag** In my thesis I discriminate between 3 categories (A,B,C) of equations. I would like to have an individual numbering for each of these categories. regardless of section, chapter or subsection... regardless of the other types. It just numbers incrementally within it's own category.

Something like this:

equation A.1

equation A.2

equation B.1

equation C.1

equation A.3

equation A.4

equation C.2

equation C.3

etc...

Is this possible ?

and how so ?

I would like to be able do customize the letters but this is less important than having multiple categories.

Any help would be greatly appreciated!

I'm not sure if this will answer your requirements, but it might.

In the preamble of your document (in other words, between the \documentclass line and the \begin{document} line), insert this:

Code:

\newcounter{eqnA}
\newcounter{eqnB}
\newcounter{eqnC}
\renewcommand{\theeqnA}{\stepcounter{eqnA}A.\arabic{eqnA}}
\renewcommand{\theeqnB}{\stepcounter{eqnB}B.\arabic{eqnB}}
\renewcommand{\theeqnC}{\stepcounter{eqnC}C.\arabic{eqnC}}

Then the input

This is equation \theeqnA.

This is equation \theeqnB.

This is equation \theeqnA.

This is equation \theeqnC.

This is equation \theeqnC.

This is equation \theeqnB.

will produce the output

This is equation A.1.

This is equation B.1.

This is equation A.2.

This is equation C.1.

This is equation C.2.

This is equation B.2.