## Section36.4Unachievable Conversions

By authoring WeBWorK problems within PreTeXt you do not need to learn all the ins and outs of PGML markup and you can concentrate on simply becoming proficient with PreTeXt. However, there are a few PreTeXt constructions which are not achievable in a WeBWorK problem for one reason or another. We list exceptions here, and also try to use source-checking tools to alert you to any differences.

• Anything that is the numbered target of a cross-reference, such as a figure, may not be inside a WeBWorK exercise. The exercise may go on to have a life of its own independent of its parent PreTeXt project, and then such a number makes no sense.

• Certain aspects of specifying borders of a PreTeXt <tabular> are not realizable in a PGML table. Specifically,

• Specifying column-specific top border attributes are not implemented.

• Cell-specific bottom border attributes are not implemented.

• medium and major table rule-thickness attributes will be handled as if they were minor.

• When constructing a list (<ul> or <ol>) specifying some number of columns (using the @cols attribute) will be ignored. PGML markup has no way to declare multicolumn lists.