Some results about $+infty$-, $-infty$- and $i$-chord functions.

The paper concerns the determination of convex bodies by values of $+\infty$-, $-\infty$- and $i$-chord functions. We prove that any at least two-dimensional convex body is not determined by values of $-\infty$-chord functions at any two internal points. We also present some positive results on the determination of convex bodies using $-\infty$- or $+\infty$- chord function at one point and $i$-chord function at another one