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$\forall$${\it es}$:ES, $X$:AbsInterface(Top), $f$:(E($X$)$\rightarrow$E($X$)).
\\[0ex]($\forall$$x$:E($X$). $f$($x$) c$\leq$ $x$)
\\[0ex]$\Rightarrow$ \=($\forall$$e$, ${\it e'}$:E($X$).\+
\\[0ex](${\it e'}$ $\in$ prior{-}$f${-}fixedpoints($e$)) $\Rightarrow$ prior{-}$f${-}fixedpoints(${\it e'}$) $\leq$ prior{-}$f${-}fixedpoints($e$))
\-
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