LP&L Trees 1 Analytical Consequence Ana Con I

Logical System


John Barwise and John Etchemendy, [1999] Language, Proof and Logic

LP&L comes with a Normal or Standard Interpretation, and this certainly affects how trees should and can behave.

For example, the polyhedra are either tetrahedra, cubes, or dodecahedra. If a particular polyhedron is a cube it cannot be a tetrahedron, so Cube(a)&Tet(a) cannot be true and a branch containing Cube(a) and Tet(a) should close or be able to close.