Unicode: 2293. Infix operator. x ⊓ y is by default interpreted as SquareIntersection[x,y].
Unicode: 2291. Infix set relation operator. x ⊑ y is by default interpreted as SquareSubsetEqual[x,y].
Unicode: 2292. Infix set relation operator. x ⊒ y is by default interpreted as SquareSupersetEqual[x,y].
Unicode: 2286. Alias: Esc sub= Esc. Infix set relation operator. x ⊆ y is by default interpreted as SubsetEqual[x,y].
Unicode: 2AB0. Infix ordering operator. x ⪰ y is by default interpreted as SucceedsEqual[x,y].
Unicode: 227D. Infix ordering operator. x ≽ y is by default interpreted as SucceedsSlantEqual[x,y].
Unicode: 227F. Infix ordering operator. x ≿ y is by default interpreted as SucceedsTilde[x,y].
Unicode: 2287. Alias: Esc sup= Esc. Infix set relation operator. x ⊇ y is by default interpreted as SupersetEqual[x,y].
\[Tau]
(Mathematica Character Name) Unicode: 03C4. Aliases: Esc t Esc, Esc tau Esc. Greek letter.
Unicode: 00FE. Alias: Esc thn Esc. Letter. Included in ISO Latin-1. Used in Icelandic and Old English.