## Definition Edit

The similiarity function XNOR is a similarity function $XNOR: \{0,1\}\times \{0,1\}\longrightarrow [0,1]$ such that $\forall x,y\in \{0,1\}$

$XNOR(x,y)= \left\{% \begin{array}{ll} 1, & \hbox{si$x=y$;} \\ 0, & \hbox{si$x\neq y$.} \\ \end{array}% \right.$
$x$ $y$ $XNOR(x,y)$
True value table for the XNOR function
0 0 1
0 1 0
1 0 0
1 1 1

## Normalization Edit

It is normalized.