I cannot remember anyone writing the letter epsilon in any other way than `\varepsilon`

in any math class; but in LaTeX `\epsilon`

and `\varepsilon`

are different symbols. Do any of you know why there are two different symbols? (I.e. if `\epsilon`

is the correct way to write the letter epsilon, why aren't mathematicians using it, and when is, according to the standards today, the correct situation to use each of the symbols?)

# Math Mode – Difference Between \varepsilon and \epsilon in LaTeX

math-modesymbolssyntax

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## Best Answer

Historically there has been a lot of confusion over the two forms, (the situation with

`\phi`

and`\varphi`

is similar but even more confused as at one point Unicode swapped the reference glyphs). I added a special section about epsilon to the XML/HTML entities spechttp://www.w3.org/2003/entities/2007doc/#epsilon

The situation in TeX is no different really, different communities used different forms of epsilon and it is rather arbitrary which one gets which name. Unicode (now) calls the curly epsilon "GREEK SMALL LETTER EPSILON" (

`ε`

) (this is a textual Greek letter rather than a math alphabetic symbol) and the symbol that TeX traditionally assigns to`\epsilon`

is called GREEK LUNATE EPSILON SYMBOL (`ϵ`

) the "symbol" being a hint that this is intended as a mathematical character rather than a textual Greek letter.From Wikipedia: