$W \, \bar{y} = \Sigma wy$
$A \, \bar{y} = \Sigma ay$
$L \, \bar{y} = \Sigma ly$
$W \, \bar{z} = \Sigma wz$
$V \, \bar{y} = \Sigma vy$
$V \, \bar{z} = \Sigma vz$
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