Chapter 1 - Section 1.3 - Propositional Equivalences - Exercises - Page 36: 48

$\underline{\quad p \quad q \quad p\downarrow q}$ $\quad T \quad T \quad F$ $\quad T \quad F \quad F$ $\quad F \quad T \quad F$ $\quad F \quad F \quad T$

p NOR q is true if and only if both p and q are false. p NOR q is denoted as $ p\downarrow q$ $\underline{\quad p \quad q \quad p\downarrow q}$ $\quad T \quad T \quad F$ $\quad T \quad F \quad F$ $\quad F \quad T \quad F$ $\quad F \quad F \quad T$