'Trees' are a type of structure within the mathematical theory of graphs.
Some logicians write Rabc to mean the application of the predicate R to the terms a,b, and c. Others write R(a,b,c). We prefer the latter. The Colin Howson book uses a notation like R(a,b,c) for the application of a predicate R to the arguments or terms a, b, c. It employs the upper case letters A-Z, perhaps followed by subscripts, to be predicates, so, for example, R, S₁, T₁2 are all predicates. The software supports this.
Welcome!
1/29/08 10Software Under construction
To become familiar with the new rules for predicate logic trees with identity.
It is possible to use trees with formulas containing identity. Two new rules are needed.
5/26/09 10Software
A. Hausman, H.Kahane, P.Tidman, [2007] Logic and Philosophy Chapter 12
Hausman [2007] has a number of exercises. Many of them you will be able to do in the Applet below.
Here are a few hints
2/3/08 10 Software
Your browser is not displaying the Deriver applet. Try downloading Deriver itself by clicking on the link elsewhere on the page.
1/23/09 10 Software
A central use for Trees is to produce a counter example to an invalid argument. To do this, you construct a tree with a complete open branch. You will be able to do this for invalid arguments (but not valid ones). Then you run up that branch assigning all atomic formulas True and all negations of atomic formulas False.
This applet will let you try a few.
2/3/08 10 Software
Your browser is not displaying the Deriver applet. Try downloading Deriver itself by clicking on the link elsewhere on the page.
1/29/08
To become familiar with the new rules for predicate logic trees.
A. Hausman, H.Kahane, P.Tidman, [2007] Logic and Philosophy Chapter 12
There are further rules for predicate logic trees (which we will come to shortly).