In a rotary assembly comprising a rotor mounted in rotation in a stator about a mean axis of rotation, a radial position sensor comprises three induction sensors distributed in the stator substantially at 120 from one another around the rotor and equidistant from the mans axis of ration. And a projection lens projects an image on the basis of the position of the part pointed by the laser pointer and detected by the pointed position detecting section andor in correspondence to the image of the pointed part. Provided are a catalyst for use in the production of sugar alcohols by the hydrolysis and hydrogenation of cellulose that affords easy separation of catalyst and product, and that does not require pH adjustment, acid or alkali neutralization, or activation of the catalyst during reuse, and a method of producing sugar alcohols from cellulose employing this catalyst. In addition, the arithmetic operational method with high priority and an argument of the arithmetic operational method with high priority are converted into a second subexpression using an arithmetic operational sign in accordance with the predetermined rule. In order to release the gate, a manually performed movement in three different directions of an actuator which affects the releasing mechanism is required. The laterally extended upper portion can contact the lower surface of the mirror plate to limit the rotation of the mirror plate.