Unsupported titles/`lsqb`

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1. (mathematics) Denotes a closed left endpoint of an interval.

   ${\displaystyle [a,b)=\{x\in \mathbb {R} \,|\,a\leq x<b\}}$

   ${\displaystyle \left[a,b\right[=\{x\in \mathbb {R} \,|\,a\leq x<b\}}$

2. (mathematics) Denotes an open right endpoint of an interval.

   ${\displaystyle \left[a,b\right[=\{x\in \mathbb {R} \,|\,a\leq x<b\}}$

   ${\displaystyle \left]a,b\right[=\{x\in \mathbb {R} \,|\,a<x<b\}}$

3. Used in [ ].

• [ ]
• ⟦

• ]

• Bracket on Wikipedia.Wikipedia

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1. Used to create digraphs that substitute for letters that do not have proper Unicode support

The digraphs [B, [b, [D, [d, [G, [g replace overstruck B̶, b̶, D̶, d̶, G̶, g̶, which do not have dedicated Unicode support. More documents (including official government publications) use the bracket hack than the single letters.