\[LeftDoubleBracket]

  • Unicode: 301A.
  • Alias: Esc[[Esc.
  • Compound operator with builtin evaluation rules.
  • m is by default interpreted as Part[m,i,j,].
  • Sometimes used in mathematics to indicate a class of algebraic objects with certain variables or extensions.
  • Extensible character; grows by default to limited size.