Search results
Results from the WOW.Com Content Network
Prentice's rule, named so after the optician Charles F. Prentice, is a formula used to determine the amount of induced prism in a lens: = where: P is the amount of prism correction (in prism dioptres) c is decentration (the distance between the pupil centre and the lens's optical centre, in millimetres)
Principal symbol. The variation formula computations above define the principal symbol of the mapping which sends a pseudo-Riemannian metric to its Riemann tensor, Ricci tensor, or scalar curvature. The principal symbol of the map assigns to each a map from the space of symmetric (0,2)-tensors on to the space of (0,4)-tensors on given by.
The fundamental theorem of Riemannian geometry can be viewed as saying that this linear system has a unique solution. This is seen via the following computation: [14] in which the metric-compatibility condition is used three times for the first equality and the torsion-free condition is used three times for the second equality.
In geometry, a Euclidean plane isometry is an isometry of the Euclidean plane, or more informally, a way of transforming the plane that preserves geometrical properties such as length. There are four types: translations, rotations, reflections, and glide reflections (see below ยง Classification ). The set of Euclidean plane isometries forms a ...
This article summarizes equations used in optics, including geometric optics, physical optics, radiometry, diffraction, and interferometry.
Truncation (geometry) Truncated square is a regular octagon: t {4} = {8} =. Truncated cube. t {4,3} or. Truncated cubic honeycomb. t {4,3,4} or. In geometry, a truncation is an operation in any dimension that cuts polytope vertices, creating a new facet in place of each vertex.
Dilution of precision ( DOP ), or geometric dilution of precision ( GDOP ), is a term used in satellite navigation and geomatics engineering to specify the error propagation as a mathematical effect of navigation satellite geometry on positional measurement precision. Understanding the geometric dilution of precision (GDOP) with a simple example.
Esophoria is an eye condition involving inward deviation of the eye, usually due to extra-ocular muscle imbalance. It is a type of heterophoria. Cause. Causes include: Refractive errors; Divergence insufficiency; Convergence excess; this can be due to nerve, muscle, congenital or mechanical anomalies.
Convergence insufficiency. Convergence Insufficiency. Other names. Convergence disorder. Specialty. Ophthalmology, optometry. Convergence insufficiency is a sensory and neuromuscular anomaly of the binocular vision system, characterized by a reduced ability of the eyes to turn towards each other, or sustain convergence .
General theorem about nested parallelograms. The theorem of gnomon is special case of a more general statement about nested parallelograms with a common diagonal. For a given parallelogram consider an arbitrary inner parallelogram having as a diagonal as well.