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*Definition:* a *proof situation*
consists of available knowledge `K` (a set of formulas assumed true) and
the goal `G` (a formula to be proved).

KG

"We (have to) prove `G` with knowledge `K`."

- The knowledge available in a particular situation is typically
*not*explicitly written down. - Knowledge at the beginning of the proof extended by all definitions and assumptions in the proof branch that led to the situation.

Author: Wolfgang Schreiner

Last Modification: November 30, 1999