What is an inverse perpetual?

An inverse perpetual is a perpetual futures contract whose underlying index is the inverse of a crypto asset’s price.

$$\text{Inverse Oracle Price} = \frac{ {k}}{\text{Oracle Price + }\varepsilon}$$

where k is a scaling factor (e.g., k = 1, k = 10^6, etc.), chosen for practical tick sizes and UI display

and e is a minimal constant unit to prevent dividing by zero.

You trade the perp on Inverse Oracle Price instead of directly on Oracle Price.