  We analyze an interferometric complementarity between one- and two-particle
interference in the general case: $V_{i}^{2}+V_{12}^{2}\leq 1$ $(i=1$, $2)$,
and further examine the relation among one-particle interference visibility
$V_{i}$, two-particle interference visibility $V_{12}$ and the predication
$P_{i}$ of the path of a single particle. An equality
$V_{i}^{2}+V_{12}^{2}+P_{i}^{2}=1$ $(i=1$, $2)$ is achieved for any pure
two-particle source, which implies the condition of the complementarity
relation to reach the upper bound and its relation to another interferometric
complementarity between path information and interference visibility of a
single particle. Meanwhile, the relationships of the complementarities and the
entanglement $E$ of the composite system are also investigated. Using nuclear
magnetic resonance techniques, the two-particle interferometric complementarity
was experimentally tested with the ensemble-averaged spin states, including two
extreme cases and an intermediate case.
