PolyèdreUn polyèdre est une forme géométrique à trois dimensions (un solide géométrique) ayant des faces planes polygonales qui se rencontrent selon des segments de droite qu'on appelle arêtes. Le mot polyèdre, signifiant à plusieurs faces, provient des racines grecques πολύς (polys), « beaucoup » et ἕδρα (hedra), « base », « siège » ou « face ». Un polyèdre est un solide dont toutes les faces sont des polygones. Les côtés de ces polygones sont appelés arêtes. Les extrémités des arêtes sont des points appelés sommets.
Volumetric displayA volumetric display device is a display device that forms a visual representation of an object in three physical dimensions, as opposed to the planar image of traditional screens that simulate depth through a number of different visual effects. One definition offered by pioneers in the field is that volumetric displays create 3D imagery via the emission, scattering, or relaying of illumination from well-defined regions in (x,y,z) space.
Lee distanceIn coding theory, the Lee distance is a distance between two strings and of equal length n over the q-ary alphabet {0, 1, ..., q − 1} of size q ≥ 2. It is a metric defined as If q = 2 or q = 3 the Lee distance coincides with the Hamming distance, because both distances are 0 for two single equal symbols and 1 for two single non-equal symbols. For q > 3 this is not the case anymore; the Lee distance between single letters can become bigger than 1. However, there exists a Gray isometry (weight-preserving bijection) between with the Lee weight and with the Hamming weight.
