A UHF flow is an infinite tensor product type action of the reals on a UHF
algebra $A$ and the flip automorphism is an automorphism of $A\otimes A$
sending $x\otimes y$ into $y\otimes x$. If $\alpha$ is an inner perturbation of
a UHF flow on $A$, there is a sequence $(u_n)$ of unitaries in $A\otimes A$
such that $\alpha_t\otimes \alpha_t(u_n)-u_n$ converges to zero and the flip is
the limit of $\Ad u_n$. We consider here whether the converse holds or not and
solve it with an additional assumption: If $A\otimes A\cong A$ and $\alpha$
absorbs any UHF flow $\beta$ (i.e., $\alpha\otimes\beta$ is cocycle conjugate
to $\alpha$), then the converse holds; in this case $\alpha$ is what we call a
universal UHF flow.