let X be set ; :: thesis: for q being FinSequence of BOOLEAN holds len (MergeSequence ((<*> (bool X)),q)) = 0

let q be FinSequence of BOOLEAN ; :: thesis: len (MergeSequence ((<*> (bool X)),q)) = 0

thus len (MergeSequence ((<*> (bool X)),q)) = len (<*> (bool X)) by Def1

.= 0 ; :: thesis: verum

let q be FinSequence of BOOLEAN ; :: thesis: len (MergeSequence ((<*> (bool X)),q)) = 0

thus len (MergeSequence ((<*> (bool X)),q)) = len (<*> (bool X)) by Def1

.= 0 ; :: thesis: verum