Go backward to Trees and CyclesGo up to TopGo forward to Other Tree Relations |

*Definition:*
Let `T` be a tree. A node `y` is called a *child* of
`x` if there is an edge from `x` to `y` in `T`:

yis child ofxinT: <=>< x,y> inEwhereE=T_{1}.

`x` is then called the *parent* of `y`:

parent _{T}(y) :=suchxinV: <x,y> inEwhereV=T_{0},E=T_{1}.

*Every node (apart from the root) has a unique parent.*

Author: Wolfgang Schreiner

Last Modification: January 26, 2000