Modus Tollendo Tollens/Proof Rule/Technical Note

Technical Note on Modus Tollendo Tollens

When invoking Modus Tollendo Tollens in a tableau proof, use the {{ModusTollens}} template:

{{ModusTollens|line|pool|statement|first|second}}

or:

{{ModusTollens|line|pool|statement|first|second|comment}}

where:

line is the number of the line on the tableau proof where Modus Tollendo Tollens is to be invoked

pool is the pool of assumptions (comma-separated list)

statement is the statement of logic that is to be displayed in the Formula column, without the $ ... $ delimiters

first is the first of the two lines of the tableau proof upon which this line directly depends, the one in the form $\phi \implies \psi$

second is the second of the two lines of the tableau proof upon which this line directly depends, the one in the form $\phi$

comment is the (optional) comment that is to be displayed in the Notes column.