It's great that you can pass method references as arguments like so:

operator fun Vector.times(scalar: Double) = mapToVector(scalar::times)

but since division isn't commutative, i can't use the same syntax for that, unless there's a way I don't know of?

operator fun Vector.div(divisor: Double) = mapToVector { it / divisor }

You could 0ass

divisor

as a second parameter to mapToVector and expect a lambda that takes 2 doubles, the second one being the divisor. Then you can pass Double::div.