First letter of the Greek alphabet.
The second form of the lower case epsilon is used as the "set membership" symbol.
Rarely used because it looks like an 'o.'
The lower-case Pi is universally used to represent that number which is the ratio of the circumference of a circle to its diameter. The upper-case Pi is used as the "product" symbol.
The capital Sigma is used as the "summation" symbol.
The two versions of lower-case Phi are used interchangeably.
Last letter of the Greek alphabet.