This is a follow-up of #22 ; we decided to follow HTML/CSS which treat things as ASCII case-insensitive. Concretely, ftp://ftp.unicode.org/Public/UNIDATA/CaseFolding.txt has this line:

017F; C; 0073; # LATIN SMALL LETTER LONG S

which means that falſe is case-insensitively equal to false. However, it is not ASCII case-insensitively equal to false (only a-z <-> A-Z equivalence are considered in that case).

Currently, the MathML Core spec just says "case-insensitive".

Note: for CSS colors, I reported w3c/csswg-drafts#4599