Definition:Lexicographic Order/Family

Definition
Let $\struct {I, \preceq}$ be a well-ordered set.

For each $i \in I$, let $\struct {S_i, \preccurlyeq_i}$ be an ordered set.

Let $\ds D = \prod_{i \mathop \in I} S_i$ be the Cartesian product of the family $\family {\struct {S_i, \preccurlyeq_i} }_{i \mathop \in I}$ indexed by $I$.

Then the lexicographic order on $D$ is defined as:
 * $\ds \struct {D, \preccurlyeq_D} := {\bigotimes_{i \mathop \in I} }^l \struct {S_i, \preccurlyeq_i}$

where $\preccurlyeq_D$ is defined as:


 * $\forall u, v \in D: u \preccurlyeq_D v \iff \begin {cases} u = v \\ \map u i \preccurlyeq_i \map v i & \text {for the $\preceq$-smallest $i \in I$ such that $\map u i \ne \map v i$} \end {cases}$