Unicode Explained

• The symbol is regarded as identical to the Greek letter (just as its particular usage).

• The symbol is included as a separate character, but it is defined as equivalent to

the Greek letter. There are two kinds of equivalence: canonical and compatibility.

• The symbol is regarded as a completely separate character.

You need to check the Unicode references for information about each individual sym-

bol. As a rough rule of thumb about symbols looking like Greek letters, mathematical

operators (like summation) exist as independent characters whereas symbols of quan-

tities and units (like pi and ohm) are identical to Greek letters or equivalent to them.

How Do I Find My Character?

Suppose you have been requested to convert some printed or handwritten text into a

digital format. (At the end of this chapter, we have such an exercise.) For English text

with no special characters, you might be able to use a scanner. But what would you do

with characters that the scanner does not recognize reliably?

Such problems are fairly common. For example, you might need to check the spelling

of a foreign name from a printed reference book, or you might need to quote some

printed material. Even standards on various notations often fail to specify the characters

unambiguously: the authoritative format of a standard is usually a printed publication,

and all you have got there is ink on paper, glyphs.

The recognition ...