Given two $x$-monotone curves xcv1 and xcv2 and an enumeration ce that specifies either the minimum or the maximum ends of the curves, compares the $y$-coordinate of the curves near their respective ends.

Returns SMALLER, EQUAL, or LARGER accordingly. More precisely, compares the $y$-coordinates of the vertical projection of a point $p$ onto predicate Parameter_space_in_x_2 evaluates to ARR_LEFT_BOUNDARY when applied to xcv1 and ce and when applied to xcv2 and ce. In this case $p$ is located far to the left, such that the result is invariant under a translation of $p$ farther to the left. If ce is evaluates to ARR_RIGHT_BOUNDARY when applied to xcv1 and ce and when applied to xcv2 and ce. In that case $p$ is located far to the right in a similar manner.

Precondition

parameter_space_in_x_2(xcv2, ce) = parameter_space_in_x_2(xcv1, ce).

parameter_space_in_x_2(xcv1, ce) $\neq$ ARR_INTERIOR.