set u = the BinOp of (bool {});
take LattStr(# (bool {}), the BinOp of (bool {}), the BinOp of (bool {}) #) ; :: thesis: ( LattStr(# (bool {}), the BinOp of (bool {}), the BinOp of (bool {}) #) is strict & not LattStr(# (bool {}), the BinOp of (bool {}), the BinOp of (bool {}) #) is empty )
thus ( LattStr(# (bool {}), the BinOp of (bool {}), the BinOp of (bool {}) #) is strict & not LattStr(# (bool {}), the BinOp of (bool {}), the BinOp of (bool {}) #) is empty ) ; :: thesis: verum