pgwide

make table span full page width. Describes the desired width of the table.
If zero, the maximum available width for the table is the (galley) width (possibly respecting current indents in force as specified by the stylesheet) of the current column of page. If non-zero, the table spans the width of the entire page (possibly causing any previous multicolumn text on the page to be balanced and any extra processing associated with column balancing and page spanning to be performed). 
Default: IMPLIED (implies value from the stylesheet if available). In the absence of an explicit value (or one implied from the stylesheet), the system should attempt to format the table into a galley column if reasonable, based on explicit colspeccolwidth values, galley column width, and possible table indentation implied by context. If any relative width specifications exist, they should continue to apply, but the unit proportion should be first based on the width uncommitted from the galley column. 
In the preceding paragraph, "if reasonable" is intended to preclude a system generating columns so narrow that the entry content is obscured by awkward line folding, or clipping. For character alignment, the content on either side of the alignment character should also be considered. No explicit algorithm for determining when a table will fit is provided. Because of the uncertainty in meaning, interchange of a table should include an explicit value for pgwide.