parent node (in a tree)

\xyoption

all

A parent node $P$ of a node $C$ in a tree is the first node which lies along the path from $C$ to the root of the tree, $R$ .

Drawn in the canonical root-at-top manner, the parent node of a node $C$ in a tree is simply the node immediately above $C$ which is connected to it.

\xymatrix{&\bullet\ar@{-}[dl]\ar@{-}[dr]&&&\inner@par\bullet&&{\color[rgb]{% 1,0,0}\bullet}\ar@{-}[dr]\ar@{-}[dl]&&\inner@par&\bullet\ar@{-}[dl]&&{\color[% rgb]{0,0,1}\bullet}&\inner@par\bullet&&&&}

Figure: A node (blue) and its parent (red.)