A new framework is proposed for general dynamic wormholes, unifying them with black holes. Both are generically defined locally by outer trapping horizons, temporal for worm-holes and spatial or null for black and white holes. Thus wormholehorizons are two-way traversible, while blackhole and whitehole horizons are only one-way traversible. It follows from the Einstein equation that the null energy condition is violated everywhere on a generic wormhole horizon. It is suggested that quantum inequalities constraining negative energy break down at such horizons. Wormhole dynamics can be developed as for blackhole dynamics, including a reversed second law and a first law involving a definition of wormhole surface gravity. Since the causal nature of a horizon can change, being spatial under positive energy and temporal under sufficient negative energy, blackholes and wormholes are interconvertible. In particular, if a wormhole's negative-energy source fails, it may collapse into a blackhole. Conversely, irradiating a blackhole horizon with negative energy could convert it into a wormhole horizon. This also suggests a possible final state of blackhole evaporation: a stationary wormhole. The new framework allows a fully dynamical description of the operation of a wormhole for practical transport, including the back-reaction of the transported matter on the wormhole. As an example of a matter model, a Klein-Gordon field with negative gravitational coupling is a source for a static wormhole of Morris and Thorne.
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