The $5$th letter of the Greek alphabet.
- Minuscules: $\epsilon$ and $\varepsilon$
- Majuscule: $\Epsilon$
The $\LaTeX$ code for \(\epsilon\) is
The $\LaTeX$ code for \(\varepsilon\) is
The $\LaTeX$ code for \(\Epsilon\) is
- $x \in S$, $S \owns x$
This notation was invented by Peano, from the first letter of the Greek word είναι, meaning is.
The $\LaTeX$ code for \(\in\) is
The $\LaTeX$ code for \(\owns\) is
Many a proof in analysis will famously start:
- "Let $\epsilon > 0$ ..."
where it is frequently left unstated that $\epsilon$ is a real number, arbitrarily small.
The $\LaTeX$ code for \(\epsilon > 0\) is
\epsilon > 0 .
- 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): Entry: epsilon