Definition:Infinitesimal/Informal Definition

Definition

An infinitesimal is a mathematical object $\delta$ resembling a (real) number such that:

$(1): \quad \delta > 0$

$(2): \quad \forall x \in \R_{>0}: \delta < x$

That is, an infinitesimal is a (strictly) positive real number which is smaller than every other (strictly) positive real number.

Also see

• Results about infinitesimals can be found here.

Sources

• 2008: Ian Stewart: Taming the Infinite ... (previous) ... (next): Chapter $8$: The System of the World: Leibniz