EDB — 1W0

[1W0]There are also other symbols used. Some texts use \(a⊂b\) to indicate that \(a⊆b\) but \(a≠b\) (as in the notes [ 3 ] ); others use a more expressive writing such as \(a⊊b\) to say that \(a⊆ b\) but \(a≠ b\). (Some even use \(a⊂ b\) instead of \(a⊆ b\), unfortunately — e.g. [ 14 ] ).