Tautologies and Validity Chapter
In this chapter the focus is on propositions whose truth values are all true. These propositions will be singled out and given a name, but first it is convenient to have notations for them.
NOTATION: If P, Q, R, etc. are statements then any proposition involving connectives and the given P, Q, R, etc. may be denoted by .F(P, Q, R, . . .) or simply by T .