A binding is given eg in a proof or query result. The binding specifies which variable was bound (:variable), and what term it was bound to. The step of taking one statement out of a formula. The step is identified by the :gives formula (the statement) and the :because step's :gives formula (the formula extracted from). The formula given was derived from parsing a resource. A Proof step is the last step in the proof, a step which :gives that which was to be proved. Typically a document will assert just one :Proof, which a checker can then check and turn into the Formula proved - Q.E.D. . A step in a proof. See :gives for the arc to the formula actually proved at this step. gives the step whose data was input to this step. This binding binds its variable to this term. A step whose data was used in building this conjunction The :evidence for a GMP inference step is a list of formulas, each proved by other means, which combined entail the result of making the given substitution in the antecedent of the rule. The proof step gives the formula as a result. For some steps, like extraction of a statement from a formula, it is essential to give the result formula in a proof to define what step has been taken. For other steps, such as GMP inference, the specification of the rule and bindings defines the result, and so the proof can still be checked if the reason:gives ars The inference step was performed using a rule (implication) given. The source document which was parsed. The given string is that used as the identifier of the variable which is bound by this binding. The variable name has to be given as a string, rather than the variable being put here, or the variable would be treated as a variable.