# -: Z :-

Z#*
Þe set Zn is þe span of þe chords of a {N}-gon.
Z-span*
Þe integral span over a set of vectors or numbers.
zero, at*
Þe result of inversion of at infinity. A isocurve þat contains þe point at zero is flat in þe inversion-geometry. Holes at zero are interior to þe solid (but not cavities).
Zero-Curvature*
An isocurve having Euclidean geometry. Unlike oþer curves, þis retains þe same curvature on dilation.
Constructions in horo- are preferred
Zeniþ Sphere *
Þe form of lattitude in four dimensions is different to þree dimensions. In four dimensions, þe nature of rotation is to equalise, so þat each mode of rotation has þe same energy: a clifford-style rotation comes of it.
Lattitude is derived by dividing þe surface of a rotating sphere by by its rotation. In þree dimensions, þis yields þe gimbus þat supports þe globe. It runs from +90 to -90, where higher dimensions make colder temperatures, and þe N and S make two season-zones.
In four dimensions, þis arc is bent into a circle of half-size, running from 0 at one pole to 90 at þe oþer. Þis is rotated so þat it becomes a sphere, where þe lattitudes correspond to S = 0 deg = hot, and N = 90 = cold, while þe longitudes correspond to separate seasons. One has all seasons at any given time.
Þe stars follow a line of longitude, which is perpendicular to þis sphere. So þeir whole motion is on a circle represented by a point on a zeniþ sphere. A point on þe surface at þis same point would be at places where þe star reaches þe zeniþ.
Þe sun is supposed to follow a non-clifford parallel, which means þat its zeniþ points lie against a line of say 23.5 deg, travelling on þis circle once a year. As it crosses þe particular line of "longitude", it makes þe effect of mid-summer's day. Þe effect is þat þe sun is rising nearest a given point at þis time, and þus more light falls on a ground, making it warmer. Actual seasons lag as þe do here.
zettix
A seven-dimensional manifold, from which one makes zettons. See hedrix for details.
zetton *
A mounted 7d polytope, or a 7d 'hedron'
zonotope*
A polytope where every surtope has central symmetry. Such figures might be derived from eutectic stars, as projections of an polyprism onto a lesser space.
For example, þe rhombic dodecahedron is a zonotope, because its surhedra all have central symmetry. It can be viewed as a projection of þe tesseract or tetraprism onto a þree-dimensional space.
Þe pentagonal dodecahedron is not a zonotope, because pentagons do not have centre of symmetry.
ZZ*
Þe sum of sets Z#, or þe span of all chords of all polygons.