Hi all I am looking for clarification on an aspect of Unicode bracket pairing, specifically in relation to the following four characters:
298D; 2990; o # LEFT SQUARE BRACKET WITH TICK IN TOP CORNER 298E; 298F; c # RIGHT SQUARE BRACKET WITH TICK IN BOTTOM CORNER 298F; 298E; o # LEFT SQUARE BRACKET WITH TICK IN BOTTOM CORNER 2990; 298D; c # RIGHT SQUARE BRACKET WITH TICK IN TOP CORNER These stand out from all other brackets listed in *BidiBrackets.txt* due to an inconsistency in pairing. I have looked for references online on where these brackets are used in the wild as mathematical symbols but have been unable to find anything useful. All other bracket pairs are listed as opener followed by closer, sometimes with several code points in between. According to the code point pairs in the first and second columns of this file, these particular brackets should be paired as the *first and fourth* and the *third and second*. Intuitively however, these would actually be *first and second* and *third and fourth* if one is to expect consistency. My guess is that there are three possibilities here: 1. The current pairing information is correct and the sequence is irregular for some historical reason 2. The pairing information is wrong and the sequence is consistent with other brackets 3. Pairing can be mixed with either left bracket used as a valid opener and either right bracket used as a valid closer; in this case, the pairing information is incomplete I'd be very grateful if anyone could clarify the situation here or if anyone knows of a resource that describes where such brackets are used in practice. Many thanks Nigel Small