This is documentation for Mathematica 6, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.2)

Other Mathematical Notation

Mathematica supports an extremely wide range of mathematical notation, although often it does not assign a pre-defined meaning to it. Thus, for example, you can enter an expression such as x y, but Mathematica will not initially make any assumption about what you mean by .
Mathematica knows that is an operator, but it does not initially assign any specific meaning to it.
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This gives Mathematica a definition for what the operator does.
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Now Mathematica can evaluate operations.
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A few of the operators whose input is supported by Mathematica.

Mathematica assigns built-in meanings to and , but not to or .
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There are some forms which look like characters on a standard keyboard, but which are interpreted in a different way by Mathematica. Thus, for example, \[Backslash] or \ displays as \ but is not interpreted in the same way as a \ typed directly on the keyboard.
The \ and characters used here are different from the \ and ^ you would type directly on a keyboard.
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Most operators work like and go in between their operands. But some operators can go in other places. Thus, for example, < and > or \[LeftAngleBracket] and \[RightAngleBracket] are effectively operators which go around their operand.
The elements of the angle bracket operator go around their operand.
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Some additional letters and letter-like forms.

You can use letters and letter-like forms anywhere in symbol names.
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is assumed to be a symbol, and so is just multiplied by a and b.
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