Message
mml:mi should contain one complete identifier. Do not separate words into characters
in individual mml:mi tags. Found "string-join(($mml-mi-seq), '')"
Rule XPath:
This rule ASSERTS the following, raising an alert if FALSE:
let $mml-mi-seq := (self::mml:mi, following-sibling::mml:mi) except following-sibling::*[not(self::mml:mi)][1]/following-sibling::*
returnexists(preceding-sibling::*[1][self::mml:mi]) or count($mml-mi-seq) lt 4 or matches(string-join($mml-mi-seq,
''), '^[A-Z]+$')