In OMDoc 1.2 we attempt to modularize the OMDoc specification. 

Here is the general plan for the structure. 

file (.dtd)  top-level elements               gives
------------------------------------------------------------------------
omdocst      definition, assertion,       math statements
             proof, example, theory       simple theory inheritance,
------------------------------------------------------------------------
omdoccth     theory-inclusion,            redundant theory structure,
             inclusion                    parametric theories
             axiom-inclusion              management of change
------------------------------------------------------------------------
omdocext     omlet, private, code         repository for system data,
                                          service calls, applets
------------------------------------------------------------------------
omdocdc      Dublin Coremetadata          DC metadata
------------------------------------------------------------------------
omdocpres    presentation	          presentation of the content
------------------------------------------------------------------------
ommdocquiz   exercise, mcq,...            exercises, multiple choice 
                                          questions



Unit           elements        [1; sec]   gives 
=========================================================================
[basic OMDoc] $doc-struc,         3.4.1     basic document infrastructure
              $omdocst            3.2       basic math infrastructure
-------------------------------------------------------------------------
              gives you a content-centered text base and allows 
              multi-language and multi-format presentation.
=========================================================================
[CD-OMDoc]    [basic] + $s-theo,  3.3.1     simple theories
-------------------------------------------------------------------------
              generalizes OpenMath CDs
=========================================================================
[Sys-OMDoc]   [basic] + $omweb    3.4.{2,3} infrastructure for math systems
-------------------------------------------------------------------------
              this gives you the addition to connect to web services, 
              like theorem provers. 
=========================================================================
[Spec-OMDoc]  [basic] + $c-theo   3.3.{2,4}  complex theory inheritance
-------------------------------------------------------------------------
              this gives you equivalence to specification standards like
	      CASL (Common Algebraic Specification Language). 
=========================================================================
[M-Ch-OMDoc]  [Spec] + $m-change  3.3.3      management of change
-------------------------------------------------------------------------
              Management of Change and full development MBase support
=========================================================================
[Pres-OMDoc]  [basic] + $pres     3.5        modular presentation
-------------------------------------------------------------------------
              presentation can be specified locally instead of in a
              general style sheet. 
=========================================================================
[Quiz-OMDoc]  [basic] + exercise  3.4.4      exercises and assessments 
-------------------------------------------------------------------------
              multiple choice questions, etc. 
=========================================================================
 
in this table I have used the following abbreviations

Applications:

[basic/Quiz-OMDoc]
   this seems to be the format for simple educational uses 
[Sys-OMDoc]
   OMDoc can be used as theorem prover Demo language and front-end 
   (cf. OMEGA), together with MBase as problem library. 
[Spec-OMDoc] 
   large-scale theory representation and re-use become possible
[M-Ch-OMDoc] 
   full support for theory development
[Pres-OMDoc] 
   large-scale educational systems, where global presentation is 
   unfeasible