What is an complex interval $[a,b]$? I'm asked to give a parametric equation for $[a,b]$ where $a,b \in \Bbb C$.
But I don't know what is meant with a complex interval ?
Is this is a line? Is this a rectangular? I have no idea, and it is nowhere defined in the book I use.

The natural interpretation is to treat $\mathbb{C}$ as a vector space over $\mathbb{R}$, and the interval as meaning a line segment. Then $[a,b] =_{\text{def}} \{\lambda a + (1-\lambda) b: 0 \leq \lambda \leq 1\}$ carries over from $a, b \in \mathbb{R}$ without change to the case where $a, b \in \mathbb{C}$.
