2.1.836 Part 4 Section 3.11.1.7, oldFormula (Old Formula)

a.   The standard states that the contents of this element are an extension on the ST_Formula simple type.

Excel requires the contents of this element to follow the grammar for a name formula, as defined in Name Formulas (§3.2.3.1.4, Name Formulas).

b.   The standard makes no mention of an xml:space attribute.

Excel uses this attribute to specify, using the W3C space preservation rules, how white space should be handled for the element's contents; its allowed values are defined by the XML 1.0 specification.