Economics

In our notes, it says that firms in a monopolistic market or a monopoly is still productive efficient in the long run as it is producing on its LRAC..as according to the notes, all points on the LRAC are considered to be productive efficient.

In wikipedia...

The long-run average cost curve depicts the per unit cost of producing a good or service in the long run when all inputs are variable. The curve is created as an envelope of an infinite number of short-run average total cost curves. The envelope is based on the point of each short-run ATC curve that provides the lowest possible average cost for each quantity of output. The LRAC curve is U-shaped, reflecting economies of scale when negatively-sloped and diseconomies of scale when positively sloped. In the long run, when all factors of production can be changed, the scale of the enterprise can be increased. In this case productive efficiency occurs at the optimum scale of output where all the possible economies of scale have been enjoyed and the firm is not large enough to experience diseconomies of scale.

So, who is right??
I have my own theory..for a monopolist, since it is deliberately having spare capacity to reduce quatity supplied to drive up profits, and since the LRAC is the envelope of all the lowest point in the SRAC, and since the monopolist isn't even producing at its lowest point of AC in the short run, then it should mean that in the long run, the monopolist ain't producing on its LRAC!!

makes sense?
someone correct me pls...