Unicode has a dedicated case folding[0][1] (as opposed to upper/lower case mapping) algorithm to cover these cases. [0] https://www.unicode.org/reports/tr21/tr

Unicode has a dedicated case folding[0][1] (as opposed to upper/lower case mapping) algorithm to cover these cases. [0] https://www.unicode.org/reports/tr21/tr21-3.html#Caseless%20Matching https://www.unicode.org/reports/tr21/tr21-3.html#Caseless%20... [1] http://userguide.icu-project.org/transforms/casemappings#TOC-Case-Folding http://userguide.icu-project.org/transforms/casemappings#TOC...