• Alias: <. • Matchfix operator. • x is by default interpreted as AngleBracket[x]. • Used in the form x to indicate expected or average value. • Called bra in quantum mechanics. • Used in the form x,y to indicate various forms of inner product. • Used in the form x,y, ... to denote an ordered set of objects. • Not the same as \[RawLess]. • Extensible character; grows by default to limited size. • See also: \[RightAngleBracket] , \[LeftFloor] , \[LeftCeiling] .
\[LeftAngleBracket]
<
x 
is by default interpreted as AngleBracket[x]. 
x
to indicate expected or average value. 
x, y
to indicate various forms of inner product. 
x, y, ... 
to denote an ordered set of objects. 