Creating arabic and alpha theorem numbering [duplicate]

For my Thesis I am stating a number of Theorems (Working Propositions actually). Using the theorem environment I do get some thing like:

WP1 My first WP

I create this by using

\begin{WP}
my first WP
\end{WP}


I have defined the WP environment with

\newtheorem{WP}{Working Proposition}


However if I add a second (and a third etc) the numbering continues 1 , 2 ,3 etc

Occasionally I would like to be able to creat a WP2a and WP2b and then continue with 3.

When and where I extend to the a,b,c etc is random.

Help is appreciated.

• – egreg Jul 18 '13 at 22:23
• @egreg Ah, I like your solution in that other question. I think I'll delete my answer to this one. – Gonzalo Medina Jul 18 '13 at 22:28
• Damn I had not found that question, I thought i searched thorough through here But if it only were that easy.... – wierts Jul 18 '13 at 23:59