The simplest curvature invariant for a
→ Riemannian manifold. It is derived from the
→ Ricci tensorR_{μν} ≡
R^{α}_{μαν}
by contracting indices.
Taking the trace of the Ricci tensor gives the Ricci scalar:
R ≡ R_{μν}g^{μnu;} = R^{μ}_{ν} =
R^{αμ}_{αμ}.
Also called → scalar curvature.

The energy density fluctuations in the → photon-baryon plasma
that bring about hotter and colder regions. This perturbation creates velocity
distributions that are out of phase with the acoustic density mode. The fluid velocity
from hot to cold regions causes blueshift of the photons, resulting in
→ quadrupole anisotropy.

Computers:
A type of central processing unit in which only one operation on data is executed at a time.
By contrast, in a vector processor, a single instruction operates simultaneously
on multiple data items.

A multiplication of two vectors giving a scalar. The scaler product of V_{1}
and V_{2} is defined by:
V_{1}.V_{2} = V_{1}.V_{2}
cos α, where V_{1} and V_{2} are the magnitudes of
the vectors and α is the angle between them. Same as dot product.
See also → vector product.

A theory put forward to provide a basis for a relativistic
generalization of the
→ MOdified Newtonian Dynamics (MOND) paradigm.
TeVeS is based on three dynamical fields: a tensor field, a vector
field, and a scalar field. In contrast to general relativity, it has
two metrics, an Einstein metric and a physical metric. TeVeS has
attracted considerable attention, since it can explain many galactic
and cosmological observations without the need for
→ dark matter.
Proposed by J. D. Bekenstein, 2004, "Relativistic gravitation theory for the modified
Newtonian dynamics paradigm", Phys. Rev. D, 70, 083509, arXiv:astro-ph/0403694.