Mathematical Relations Dr Ron Smith Graceland University Mathematical

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Mathematical Relations Dr. Ron Smith Graceland University

Mathematical Relations Dr. Ron Smith Graceland University

Mathematical relations n We can draw a picture to illustrate a relation between members

Mathematical relations n We can draw a picture to illustrate a relation between members of a set. Me Widow Father Daughter

Mathematical Relations n Spouse Me Widow Father Daughter

Mathematical Relations n Spouse Me Widow Father Daughter

Mathematical Relations n n This is a directed graph (digraph). Dots are vertices, arrows

Mathematical Relations n n This is a directed graph (digraph). Dots are vertices, arrows are edges. Me Widow Father Daughter

Mathematical Relations n Birth Parent Me Widow Father Daughter

Mathematical Relations n Birth Parent Me Widow Father Daughter

Mathematical relations n n A step parent is the spouse of a birth parent.

Mathematical relations n n A step parent is the spouse of a birth parent. A parent is either a birth parent or a step parent. A grandparent is a parent of a parent. We combine these simpler relations to get the complex relation “Grandparent”

Adjacency Matrices n Construct an adjacency matrix for “Spouse”. Me Father S= Widow Daughter

Adjacency Matrices n Construct an adjacency matrix for “Spouse”. Me Father S= Widow Daughter M F W D 0 0 1 1 0 0 0 0

Adjacency Matrices n “Birth Parent” Me Father B= Widow Daughter M F W D

Adjacency Matrices n “Birth Parent” Me Father B= Widow Daughter M F W D 0 0 1 0 0 0 0 0 1 0

Adjacency Matrices n n To combine “Spouse” and “Birth Parent” to get “Step Parent”

Adjacency Matrices n n To combine “Spouse” and “Birth Parent” to get “Step Parent” we simply multiply the adjacency matrices! To combine “Birth Parent” or “Step Parent” to get “Parent” we add the adjacency matrices.

A step parent is the spouse of a birth parent Spouse OF Birth Parent

A step parent is the spouse of a birth parent Spouse OF Birth Parent 0 0 1 0 0 0 1 1 0 0 0 0 0 1 0 0 0 Me Widow Father Daughter Step Parent!

A parent is a birth parent OR a step parent Birth Parent OR Step

A parent is a birth parent OR a step parent Birth Parent OR Step Parent 0 0 0 0 1 1 0 0 0 0 0 0 0 1 0 0 0 Me Widow Father Daughter Parent!

Technical Note n n n We need to use computer logic instead of arithmetic

Technical Note n n n We need to use computer logic instead of arithmetic x AND y = 1 if x and y are both 1, and 0 otherwise. We use • to stand for AND 1 • 1= 1 0 • 1= 0 1 • 0= 0 0 • 0= 0

Technical Note n n x OR y is 1 if either x or y

Technical Note n n x OR y is 1 if either x or y (or both) is 1, and 0 otherwise. We use + to stand for OR 1+1=1 0+1=1 1+0=1 0+0=0

Technical Note n n In fact, the logical operations AND and OR work exactly

Technical Note n n In fact, the logical operations AND and OR work exactly like multiplication and addition except for the fact that 1+1=1 instead of 2. If we do matrix operations using AND and OR on adjacency matrices, we get the adjacency matrix of the combined relation!

A grandparent is a parent of a parent Parent OF Parent 0 0 0

A grandparent is a parent of a parent Parent OF Parent 0 0 0 1 1 0 0 0 1 0 0 0 1 Me Widow Father Daughter Grandparent!

I’m my own Grandpa! I’m my own Grandpa, And my daughter’s her own Grandma,

I’m my own Grandpa! I’m my own Grandpa, And my daughter’s her own Grandma, It seems funny, I know, but I Mathematically show-- that I’m my own Grandpa!

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