MathML::Entities a content conversion filter for named XHTML+MathML
entities. There are over two thousand named entities in the XHTML+MathML
DTD. All the Entities defined in the XHTML+MathML DTD except the five
"safe" ones (<, >, &, ", '), will be converted to the
equivalent numeric character references or to utf-8 characters. Named
entities which are not in the XHTML+MathML DTD are escaped. This makes the
resulting XHTML (or XHTML+MathML) safe for consumption by non-validating
XML parsers.

Unlike, HTML::Entities, the mapping between MathML named entities and
codepoints is many-to-one. Therefore, there's no particular sense in
having an inverse function, which takes codepoints to named entities.

Based on: HTML::Entities by Koichi Taniguchi <taniguchi@livedoor.jp>

WWW: https://metacpan.org/release/MathML-Entities