barwise

LP&L Trees 0 Video: Advanced Tarksi World Tree

Topic
Logical System
1/29/2020

Reading

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

This video shows extending, closing, and Analytical Consequence for a pretty advanced example tree. The tree itself is broad, spreading a long way from left to right. This leads to some scrolling back and forth because the applet is being held to the width of a printable page.

LP&L Trees 1 Analytical Consequence Ana Con I

Topic
Logical System
1/28/2020

Reading

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.