Variants of English Letters

Some commonly used variants of English letters.

By using menu items in the notebook front end, you can make changes in the font and style of ordinary text. However, such changes are usually discarded whenever you send input to the Mathematica CalcCenter kernel.
Script, gothic and double-struck characters are however treated as fundamentally different from their ordinary forms. This means that even though a C that is italic or a different size will be considered equivalent to an ordinary C when fed to the kernel, a double-struck will not.

In standard mathematical notation, capital script and gothic letters are sometimes used interchangeably. The double-struck letters, sometimes called blackboard or openface letters, are conventionally used to denote specific sets. Thus, for example, conventionally denotes the set of complex numbers, and the set of integers.
Dotless i and j are not usually taken to be different in meaning from ordinary i and j; they are simply used when overscripts are being placed on the ordinary characters.

Complete alphabets of variant English letters.