fiLl in the Blanks $\downarrow \text { " for "nor," } ( x \downarrow x ) \downarrow ( y \downarrow y )$

Short Answer

fill in the blanks.
-Using $\downarrow \text { " for "nor," } ( x \downarrow x ) \downarrow ( y \downarrow y )$ can be written in terms of , +, and · as ____.