Lexicon of Arguments

 

Thiel I 92
Substitution/Thiel: >Substitution rule: if you replace all equal letters with the same correct formula or another letter. >Separation rule: A,A > B >>B (?)
So "if, then" are introduced by simple rules, negation of a statement ..+... def "designated formula".... "allocation".
>modus ponens, >Introduction.
I 95
Some of the formulas formed with the help of the newly added negation sign are not designated formulas.
For example, one of the assignments of the formula ~~p > p is the expression (~~1) >1. Its value is calculated according to the tables as (~~1) x 1 = (~2) x 1 = 0 x 1 = 1
The assignment also receives
0 > (~~0) of the formula p > ~~p the value
0 x (~~0) = 0 x (~1) = 0 x 2 = 1. If the value is different from 0, there is no designated formula regarding our table.
>Formulas.