Ochlophobia Ochlophobia Ochlophobia ("Fear of Crowds") and demophobia ("Fear of Unruly Mobs") are terms for types of social phobia or social anxiety disorder whose sufferers have a fear of crowds. Sufferers may offer various rationalizations of the phobia, such as the fear being trampled in a crowd, getting a deadly disease from people within the crowd, getting lost in the crowd, or feeling insignificant when surrounded by a crowd. People who are shy and introverted are most likely to experience ochlophobia, but not all introverts have anxiety problems. Ochlophobic people are often unable to handle situations involving parties, going to theaters,
Irrational rotation Irrational rotation In the mathematical theory of dynamical systems, an irrational rotation is a map where "θ" is an irrational number. Under the identification of a circle with R/Z, or with the interval [0, 1] with the boundary points glued together, this map becomes a rotation of a circle by a proportion "θ" of a full revolution (i.e., an angle of 2"πθ" radians). Since "θ" is irrational, the rotation has infinite order in the circle group and the map "T" has no periodic orbits. Alternatively, we can use multiplicative notation for an irrational rotation by introducing the map The relationship