Classical unified field theories a survey of classical relativistic field theories of gravitation that have been motivated by theoretical concerns other than unification, see Classical theories of gravitation. For a survey of current work toward creating a quantum theory of gravitation, see quantum gravity. The early attempts at creating a unified field theory began with the Riemannian geometry of general relativity, and attempted to incorporate electromagnetic fields into a more general geometry, since ordinary Riemannian geometry seemed incapable of expressing the properties of the electromagnetic field. Einstein was not alone in his attempts to unify electromagnetism and gravity; a large number of mathematicians and
Unified voicemail Unified voicemail Unified voicemail is the combination of different voicemail bearers into a single voicemail system. Using dedicated DID /DDI numbers for each mailbox, the mailbox can be used on a variety of devices and end-points. This is similar to what GSM providers use for their voicemail systems. Mobile phones and traditional analog phones need to support conditional call diversion to enjoy unified voicemail. Unified voicemail can be extended into unified messaging as already used. Some telephone users have several telephone accounts, which may include home, work, mobile, and SIP numbers. Unified voicemail provides a single voicemail for several accounts.