# Definition:Logical NOR/Notational Variants

## Definition

Various symbols are encountered that denote the concept of logical NOR:

Symbol Origin Known as
$p \downarrow q$ Willard Quine Quine arrow
$p \ \mathsf{NOR} \ q$
$p \mathop \bot q$
$p \curlywedge q$ Charles Sanders Peirce Ampheck

The all-uppercase rendition NOR originates from the digital electronics industry, where, because NOR is Functionally Complete, this operator has a high importance.