thus
dom (mlt r,X) = [#] X
by FUNCT_2:def 1; TOPS_2:def 5 ( rng (mlt r,X) = [#] X & mlt r,X is one-to-one & mlt r,X is continuous & (mlt r,X) " is continuous )
thus
rng (mlt r,X) = [#] X
by Th48; ( mlt r,X is one-to-one & mlt r,X is continuous & (mlt r,X) " is continuous )
thus
mlt r,X is one-to-one
by Lm14; ( mlt r,X is continuous & (mlt r,X) " is continuous )
thus
mlt r,X is continuous
by Lm15; (mlt r,X) " is continuous
(mlt r,X) " = mlt (r " ),X
by Th49;
hence
(mlt r,X) " is continuous
by Lm15; verum