Say you have sets $A$ and $B$, whereby $A$ contains elements $a_1$, $a_2$, and $a_3$, and $B$ contains $b_1$, $b_2$, and $b_3$.
The two sets have a one-to-one relationship in such a way that $a_1$ maps to $b_1$, $a_2$ to $b_2$, and $a_3$ to $b_3$.
What do you call, however, a one-to-one relationship that never changes, i.e, one that's static? So if $a_1$ now maps to $b_2$ and $a_2$ to $b_1$ (with $a_1$ and $b_1$ and $a_2$ and $b_2$ no longer being connected, respectively), it's still a one-to-one relationship, but it's a dynamic one. If this isn't something that's possible (for whatever reason), what type of one-to-one relationship do you call this?