---- > [!definition] Definition. ([[relation]]) > A **relation** on a set $A$ is a subset $C$ of the [[cartesian product]] $A \times A$. \ For a **relation** $C \subset A \times A$ we use the notation $xCy$ to indicate $(x,y)\in C$, read "$x$ is in the relation $C$ to $yquot;. ---- #### ---- #### References > [!backlink] > ```dataview > TABLE rows.file.link as "Further Reading" > FROM [[]] > FLATTEN file.tags as Tag > WHERE Tag = "#definition" OR Tag = "#theorem" OR Tag = "#MOC" OR Tag = "#proposition" OR Tag = "#axiom" > GROUP BY Tag > ``` > [!frontlink] > ```dataview > TABLE rows.file.link as "Further Reading" > FROM outgoing([[]]) > FLATTEN file.tags as Tag > WHERE Tag = "#definition" OR Tag = "#theorem" OR Tag = "#MOC" OR Tag = "#proposition" OR Tag = "#axiom" > GROUP BY Tag > ```