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#1 2007-04-27 03:49:15

jim1
Member
Registered: 2007-04-27
Posts: 4

Discrete Math

See attachment is the rooted tree:

(a) the root
(b) the internal verticies
(c) the terminal verticies
(d) the parent of G
(e) the childeren of B
(f) the descendents of D
(g) the ancestors of H

How do you figure this one out? Please Help.

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#2 2007-04-27 04:03:37

Ricky
Moderator
Registered: 2005-12-04
Posts: 3,791

Re: Discrete Math

Jim, I get the feeling you don't know what the definitions of those things are.  Simply look them up and the answer will be failry obvious.


"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

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#3 2007-04-27 04:23:05

jim1
Member
Registered: 2007-04-27
Posts: 4

Re: Discrete Math

U-is a parent of V
V-is a child of U
V-is a descendent of the vertices
Terminal vertex is a vertex that has no children
Internal vertex is one that has children. 

I am reading for understanding but its not clear.

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#4 2007-04-27 15:17:16

George,Y
Member
Registered: 2006-03-12
Posts: 1,379

Re: Discrete Math

If interpreted as a family tree,
the root is apparently C
the parent of G is C for sure,
and the ancestor is C for the rest of everyone.

CGHAB all have children, so they are internals while the rest are terminals.


X'(y-Xβ)=0

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#5 2007-04-27 15:50:29

jim1
Member
Registered: 2007-04-27
Posts: 4

Re: Discrete Math

Thanks for the help.

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#6 2007-04-27 23:25:18

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: Discrete Math

Just in case you don't know, parents are different from ancestors and children are different from descendants. Parents and children are exactly one level away from whatever point we're talking about, but ancestors and descendants just have to be connected.

For example, I's parent is B, but its ancestors are C, A and B.


Why did the vector cross the road?
It wanted to be normal.

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