2.1.1653 Part 1 Section 22.214.171.124, mathFont (Math Font)
a. The standard does not limit the length of the value of the val attribute.
Word restricts the value of this attribute to be at most 31 characters.
b. The standard says that the mathFont property is the default math font.
Word uses this setting when math is created while editing within the application, but not when loading math from a file.
c. The standard does not specify conditions under which the default math font should be ignored.
Word ignores the default math font if it is set to an empty string or font which is not appropriate for displaying math.
d. The standard implies that the val attribute is optional.
Word requires this attribute.