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In studies that used standardized definitions of convergence insufficiency, investigators have reported a prevalence of 4.2–6% in school and clinic settings. The standard definition of convergence insufficiency is exophoria greater at near than at distance, a receded near point of convergence, and reduced convergence amplitudes at near. [4]
Exophoria. Exophoria is a form of heterophoria in which there is a tendency of the eyes to deviate outward. [ 1] During examination, when the eyes are dissociated, the visual axes will appear to diverge away from one another. [ 2] The axis deviation in exophoria is usually mild compared with that of exotropia .
Fixation disparity. Fixation disparity is a tendency of the eyes to drift in the direction of the heterophoria. While the heterophoria refers to a fusion-free vergence state, the fixation disparity refers to a small misalignment of the visual axes when both eyes are open in an observer with normal fusion and binocular vision. [1]
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogram prism. Hence two pairs of vectors are perpendicular (meet at right ...
The sum over r covers other degrees of freedom specific for the field, such as polarization or spin; it usually comes out as a sum from 1 to 2 or from 1 to 3. E p is the relativistic energy for a momentum p quantum of the field, = m 2 c 4 + c 2 p 2 {\textstyle ={\sqrt {m^{2}c^{4}+c^{2}\mathbf {p} ^{2}}}} when the rest mass is m .
The Weyl group of SO(2n + 1) is the semidirect product {} of a normal elementary abelian 2-subgroup and a symmetric group, where the nontrivial element of each {±1} factor of {±1} n acts on the corresponding circle factor of T × {1} by inversion, and the symmetric group S n acts on both {±1} n and T × {1} by permuting factors.
The most common examples are the curves X(N), X 0 (N), and X 1 (N) associated with the subgroups Γ(N), Γ 0 (N), and Γ 1 (N). The modular curve X(5) has genus 0: it is the Riemann sphere with 12 cusps located at the vertices of a regular icosahedron. The covering X(5) → X(1) is realized by the action of the icosahedral group on the
Proof of Bertrand's postulate. In mathematics, Bertrand's postulate (now a theorem) states that, for each , there is a prime such that . First conjectured in 1845 by Joseph Bertrand, [1] it was first proven by Chebyshev, and a shorter but also advanced proof was given by Ramanujan. [2]