Sets the “INCLUDE” or “IGNORE” marked section switch for
the MATHML Tag Set. This switch determines whether the math processing in
the appropriate MathML Tag Set (%mathml2.dtd; or %mathml3.dtd;) module or the %xmlspecchars.ent; module will invoke the sets of special characters that are defined AND INVOKED in the %xmlspecchars.ent; module. A value of “IGNORE” turns off the second invocation, which is located in the MathML Tag Set.