A relational symbol indicating precedence or ordering where one element is less than or equal to another in partial orders.
Examples
Partial ordering relation
a \preceq b \text{ and } b \preceq c \implies a \preceq c
Matrix inequality
A \preceq B \text{ means matrix } A-B \text{ is negative semidefinite}
Comparing sequences
\{a_n\} \preceq \{b_n\} \text{ if } a_n \leq b_n \text{ for all } n