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Single Idea 13613

[from 'Intermediate Logic' by David Bostock, in 5. Theory of Logic / H. Proof Systems / 5. Tableau Proof ]

Full Idea

An open branch in a completed tableau will always yield an interpretation that verifies every formula on the branch.

Gist of Idea

A completed open branch gives an interpretation which verifies those formulae

Source

David Bostock (Intermediate Logic [1997], 4.7)

Book Reference

Bostock,David: 'Intermediate Logic' [OUP 1997], p.177


A Reaction

In other words the open branch shows a model which seems to work (on the available information). Similarly a closed branch gives a model which won't work - a counterexample.

Related Idea

Idea 7790 If an argument is invalid, a truth tree will indicate a counter-example [Girle]