Unicode: 21D4. Alias: Esc <=> Esc. Infix arrow operator. x ⇔ y is by default interpreted as DoubleLeftRightArrow[x,y]. Used in mathematics to indicate logical equivalence. ...
Unicode: 22A8. Infix operator. x ⊨ y is by default interpreted as DoubleRightTee[x,y]. x ⊨ y ⊨ z groups as x ⊨ (y ⊨ z). Used in mathematics to indicate various strong forms ...
Unicode: 2193. Infix arrow operator. x ↓ y is by default interpreted as DownArrow[x,y]. Used to indicate monotonic decrease to a limit. Sometimes used for logical nor. ...
Unicode: 2026. Alias: Esc ... Esc. Letter-like form. Used to indicate omitted elements in a row of a matrix. \[Ellipsis] on its own will act as a symbol.
Unicode: 25E6. Alias: Esc esci Esc. Letter-like form. Not the same as the infix operator \[SmallCircle]. Used as an overscript to add ring diacritical marks.
Unicode: 25A1. Alias: Esc esq Esc. Letter-like form. Not the same as the operator \[Square]. Not the same as \[Placeholder].
Unicode: 25B3. Letter-like form. Used in geometry to indicate a triangle, as in the symbol △ABC. Not the same as \[CapitalDelta].
Unicode: 21CC. Alias: Esc equi Esc. Infix arrow-like operator. x ⇌ y is by default interpreted as Equilibrium[x,y]. Used in chemistry to represent a reversible reaction. ...
Unicode: 25A0. Alias: Esc fsq Esc. Letter-like form. Used as a dingbat. Not the same as \[SelectionPlaceholder].
Unicode: 03C2. Alias: Esc fs Esc. Greek letter. Used in written Greek when σ occurs at the end of a word. Not commonly used in technical notation. Not the same as \[Stigma].