MA111: Contemporary mathematics Jack Schmidt University of Kentucky - - PowerPoint PPT Presentation

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MA111: Contemporary mathematics Jack Schmidt University of Kentucky - - PowerPoint PPT Presentation

. . MA111: Contemporary mathematics Jack Schmidt University of Kentucky November 30, 2011 Schedule: 25 homework questions up: 10 are due by Fri Dec 16, 2011. Final Exam: 006: Friday 8am in CB242; Alt is Monday 1pm in CB238, Wed 8:30pm in


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SLIDE 1

. .

MA111: Contemporary mathematics

Jack Schmidt

University of Kentucky

November 30, 2011

Schedule: 25 homework questions up: 10 are due by Fri Dec 16, 2011. Final Exam: 006: Friday 8am in CB242; Alt is Monday 1pm in CB238, Wed 8:30pm in CB118 007: Monday 1pm in CB238; Alt is Friday 8am in CB242, Wed 8:30pm in CB118 3.6: Today we will study how to divide the undivisible.

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SLIDE 2

Amelia and Bill get (amicably) divorced

They jointly own a house. How do they split it? Amelia gets downstairs, Bill gets upstairs? Amelia gets the house on MWF and Bill on TRS, and they have a picnic on Sunday? They sell the house and split the money? Flip a coin; winner gets the house, but pays the loser the “fair market value” of the house

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SLIDE 3

Amelia and Bill get (amicably) divorced

They jointly own a house. How do they split it? Amelia gets downstairs, Bill gets upstairs? Amelia gets the house on MWF and Bill on TRS, and they have a picnic on Sunday? They sell the house and split the money? Flip a coin; winner gets the house, but pays the loser the “fair market value” of the house

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SLIDE 4

Amelia and Bill get (amicably) divorced

They jointly own a house. How do they split it? Amelia gets downstairs, Bill gets upstairs? Amelia gets the house on MWF and Bill on TRS, and they have a picnic on Sunday? They sell the house and split the money? Flip a coin; winner gets the house, but pays the loser the “fair market value” of the house

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SLIDE 5

Amelia and Bill get (amicably) divorced

They jointly own a house. How do they split it? Amelia gets downstairs, Bill gets upstairs? Amelia gets the house on MWF and Bill on TRS, and they have a picnic on Sunday? They sell the house and split the money? Flip a coin; winner gets the house, but pays the loser the “fair market value” of the house

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SLIDE 6

Amelia and Bill get (amicably) divorced

They jointly own a house. How do they split it? Amelia gets downstairs, Bill gets upstairs? Amelia gets the house on MWF and Bill on TRS, and they have a picnic on Sunday? They sell the house and split the money? Flip a coin; winner gets the house, but pays the loser the “fair market value” of the house

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SLIDE 7

Amelia and Bill have their own ideas

Bill hates the house. The fair market value is $150k, but he wants it sold now, and would take $120k today. Amelia loves the house and has spent about $50k of loving attention improving the house in little ways only she can see. She wouldn’t sell it for less than $200k. . . A: $200k . B: $120k

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SLIDE 8

Coin flip for the win

Is the coin-flip and pay method fair? Well it is certainly random. Flip a coin: Bill gets the house, Amelia gets the money. . . Amelia: $75k of $200k . $75k . A: $200k . Bill: $45k of $120k .

  • $75k

. B: $120k Neither thinks this is fair! Both got only 37.5% of the house! 25% of the house was lost and everyone is mad!

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SLIDE 9

Coin flip for the win

Is the coin-flip and pay method fair? Well it is certainly random. Flip a coin: Bill gets the house, Amelia gets the money. . . Amelia: $75k of $200k . $75k . A: $200k . Bill: $45k of $120k .

  • $75k

. B: $120k Neither thinks this is fair! Both got only 37.5% of the house! 25% of the house was lost and everyone is mad!

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SLIDE 10

Coin flip for the win

Is the coin-flip and pay method fair? Well it is certainly random. Flip a coin: Bill gets the house, Amelia gets the money. . . Amelia: $75k of $200k . $75k . A: $200k . Bill: $45k of $120k .

  • $75k

. B: $120k Neither thinks this is fair! Both got only 37.5% of the house! 25% of the house was lost and everyone is mad!

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SLIDE 11

Who should really get the house?

Amelia wants the house more, Bill wants the money more. If they just trade, things are much better: . . Amelia: $125k of $200k .

  • $75k

. A: $200k . Bill: $75k of $120k . $75k . B: $120k They are both happy: Amelia gets 62.5%, Bill gets 62.5%. An extra 25% of the house was created from nothing!

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SLIDE 12

Auctions and compensation agreements

Several people jointly own an item Submit sealed bids One of the bidders is given the item in exchange for their bid The bid is divided amongst the others somehow So two questions:

Which bid gets the item? How to split the money?

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SLIDE 13

Game 1: Sweeny’s auction house

High bid wins. Each player gets their fair share of their own bid amount. Sweeny keeps the rest , suckers. Is this “fair” according to the book? Is this “nice” according to you? Amelia: House - $100k = 50% Bill: $60k = 50% Sweeny: $40k = %

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SLIDE 14

Game 1: Sweeny’s auction house

High bid wins. Each player gets their fair share of their own bid amount. Sweeny keeps the rest , suckers. Is this “fair” according to the book? Is this “nice” according to you? Amelia: House - $100k = 50% Bill: $60k = 50% Sweeny: $40k = %

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SLIDE 15

Game 1: Sweeny’s auction house

High bid wins. Each player gets their fair share of their own bid amount. Sweeny keeps the rest , suckers. Is this “fair” according to the book? Is this “nice” according to you? Amelia: House - $100k = 50% Bill: $60k = 50% Sweeny: $40k = %

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SLIDE 16

Game 1: Sweeny’s auction house

High bid wins. Each player gets their fair share of their own bid amount. Sweeny keeps the rest, suckers. Is this “fair” according to the book? Is this “nice” according to you? Amelia: House - $100k = 50% Bill: $60k = 50% Sweeny: $40k = %

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SLIDE 17

Game 1: Sweeny’s auction house

High bid wins. Each player gets their fair share of their own bid amount. Sweeny keeps the rest, suckers. Is this “fair” according to the book? Is this “nice” according to you? Amelia: House - $100k = 50% Bill: $60k = 50% Sweeny: $40k = %

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SLIDE 18

Game 1: Sweeny’s auction house

High bid wins. Each player gets their fair share of their own bid amount. Sweeny keeps the rest, suckers. Is this “fair” according to the book? Is this “nice” according to you? Amelia: House - $100k = 50% Bill: $60k = 50% Sweeny: $40k = %

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SLIDE 19

Game 1: Sweeny’s auction house

High bid wins. Each player gets their fair share of their own bid amount. Sweeny keeps the rest, suckers. Is this “fair” according to the book? Is this “nice” according to you? Amelia: House - $100k = 50% Bill: $60k = 50% Sweeny: $40k = ∞%

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SLIDE 20

Game 2: No bid left behind

High bid wins. Split the money equally. Is this “fair” according to the book? Is this “nice” according to you? Everyone gets an equal payout, but some are more equal than others: Amelia: House - $100k = 50% Bill: $100k = 83.3% Fair, Envy-free, Pareto Optimal, not equitable

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SLIDE 21

Game 2: No bid left behind

High bid wins. Split the money equally. Is this “fair” according to the book? Is this “nice” according to you? Everyone gets an equal payout, but some are more equal than others: Amelia: House - $100k = 50% Bill: $100k = 83.3% Fair, Envy-free, Pareto Optimal, not equitable

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SLIDE 22

Game 2: No bid left behind

High bid wins. Split the money equally. Is this “fair” according to the book? Is this “nice” according to you? Everyone gets an equal payout, but some are more equal than others: Amelia: House - $100k = 50% Bill: $100k = 83.3% Fair, Envy-free, Pareto Optimal, not equitable

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SLIDE 23

Game 2: No bid left behind

High bid wins. Split the money equally. Is this “fair” according to the book? Is this “nice” according to you? Everyone gets an equal payout, but some are more equal than others: Amelia: House - $100k = 50% Bill: $100k = 83.3% Fair, Envy-free, Pareto Optimal, not equitable

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SLIDE 24

Game 2: No bid left behind

High bid wins. Split the money equally. Is this “fair” according to the book? Is this “nice” according to you? Everyone gets an equal payout, but some are more equal than others: Amelia: House - $100k = 50% Bill: $100k = 83.3% Fair, Envy-free, Pareto Optimal, not equitable

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SLIDE 25

Game 2: No bid left behind

High bid wins. Split the money equally. Is this “fair” according to the book? Is this “nice” according to you? Everyone gets an equal payout, but some are more equal than others: Amelia: House - $100k = 50% Bill: $100k = 83.3% Fair, Envy-free, Pareto Optimal, not equitable

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SLIDE 26

Game 3: An average idea

High bid wins. Each loser gets W B

T

where

W is the winning bid, B is their own bid, T is the total of all the bids

Amelia: House k k % Bill: k % People get different amounts, but always the same percentage Fair, Pareto Optimal, Equitable, not Envy-free

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SLIDE 27

Game 3: An average idea

High bid wins. Each loser gets W·B

T

where

W is the winning bid, B is their own bid, T is the total of all the bids

Amelia: House k k % Bill: k % People get different amounts, but always the same percentage Fair, Pareto Optimal, Equitable, not Envy-free

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SLIDE 28

Game 3: An average idea

High bid wins. Each loser gets W·B

T

where

W is the winning bid, B is their own bid, T is the total of all the bids

Amelia: House − $75k = $125k = 62.5% Bill: 200·120

320

= $75k = 62.5% People get different amounts, but always the same percentage Fair, Pareto Optimal, Equitable, not Envy-free

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SLIDE 29

Game 3: An average idea

High bid wins. Each loser gets W·B

T

where

W is the winning bid, B is their own bid, T is the total of all the bids

Amelia: House − $75k = $125k = 62.5% Bill: 200·120

320

= $75k = 62.5% People get different amounts, but always the same percentage Fair, Pareto Optimal, Equitable, not Envy-free

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SLIDE 30

Game 3: An average idea

High bid wins. Each loser gets W·B

T

where

W is the winning bid, B is their own bid, T is the total of all the bids

Amelia: House − $75k = $125k = 62.5% Bill: 200·120

320

= $75k = 62.5% People get different amounts, but always the same percentage Fair, Pareto Optimal, Equitable, not Envy-free

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SLIDE 31

Game 4: Knaster’s method

High bid wins. Everyone gets back their fair share. The rest is split evenly, none for Sweeny. Amelia: House k k k k % Bill: k k k % Fair, Pareto Optimal, not Envy-free, not Equitable However, it is a good compromise between envy-free and equitable Bill got less value, but more percentage. This is the book’s chapter 3.6.

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SLIDE 32

Game 4: Knaster’s method

High bid wins. Everyone gets back their fair share. The rest is split evenly, none for Sweeny. Amelia: House k k k k % Bill: k k k % Fair, Pareto Optimal, not Envy-free, not Equitable However, it is a good compromise between envy-free and equitable Bill got less value, but more percentage. This is the book’s chapter 3.6.

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SLIDE 33

Game 4: Knaster’s method

High bid wins. Everyone gets back their fair share. The rest is split evenly, none for Sweeny. Amelia: House − $200k + $100k + $20k = $120k = 60% Bill: $60k + $20k = $80k = 66.7% Fair, Pareto Optimal, not Envy-free, not Equitable However, it is a good compromise between envy-free and equitable Bill got less value, but more percentage. This is the book’s chapter 3.6.

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SLIDE 34

Game 4: Knaster’s method

High bid wins. Everyone gets back their fair share. The rest is split evenly, none for Sweeny. Amelia: House − $200k + $100k + $20k = $120k = 60% Bill: $60k + $20k = $80k = 66.7% Fair, Pareto Optimal, not Envy-free, not Equitable However, it is a good compromise between envy-free and equitable Bill got less value, but more percentage. This is the book’s chapter 3.6.

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SLIDE 35

Game 4: Knaster’s method

High bid wins. Everyone gets back their fair share. The rest is split evenly, none for Sweeny. Amelia: House − $200k + $100k + $20k = $120k = 60% Bill: $60k + $20k = $80k = 66.7% Fair, Pareto Optimal, not Envy-free, not Equitable However, it is a good compromise between envy-free and equitable Bill got less value, but more percentage. This is the book’s chapter 3.6.

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SLIDE 36

Game 4: Knaster’s method

High bid wins. Everyone gets back their fair share. The rest is split evenly, none for Sweeny. Amelia: House − $200k + $100k + $20k = $120k = 60% Bill: $60k + $20k = $80k = 66.7% Fair, Pareto Optimal, not Envy-free, not Equitable However, it is a good compromise between envy-free and equitable Bill got less value, but more percentage. This is the book’s chapter 3.6.