First of all. What is a name.
A Name is a set of characters used for naming constantes, functions and labels.
The only obligations for a name is that it must not contain any '(' or ')' or space character.
Then, when using the name, you must know sone things.
When using a name, you must put first a '=' char before it (in fact, '=' is a hiden caracter add at the begining of each name to allows to diferanciate local lables from functions and constantes names).
If the name you want to use contains sone mathematical characters, you must protect the name using '"' characters.
Rules on labels names are a litle worst.
A label may not begin with a non alphabetic char.
A label may only contain alphanumeric chars.