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Page 1: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess and �Natural Laws�

How might human decision regularities appear in other domains?

Kenneth W. Regan1

University at Bu�alo (SUNY)

UB CSE 501, 11/13/2018

Password: Vicki Hanson

1Joint work with Tamal Tanu Biswas and with grateful acknowledgment to UB'sCenter for Computational Research (CCR)

Page 2: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess and �Natural Laws�

How might human decision regularities appear in other domains?

Kenneth W. Regan1

University at Bu�alo (SUNY)

UB CSE 501, 11/13/2018 Password: Vicki Hanson

1Joint work with Tamal Tanu Biswas and with grateful acknowledgment to UB'sCenter for Computational Research (CCR)

1Joint work with Tamal Tanu Biswas and with grateful acknowledgment to UB'sCenter for Computational Research (CCR)

Page 3: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess and Natural Laws

Logistic Laws.https://rjlipton.wordpress.com/2012/03/30/when-is-a-law-natural/

The Win-Expectation Curve:https://rjlipton.wordpress.com/2016/12/08/magnus-and-the-turkey-grinder/

Relative Perception of Value:https://rjlipton.wordpress.com/2016/11/30/when-data-serves-turkey/

Predictive Analytics: Inferring the probabilities pj of various eventsj :

Risk or damage events.

Voter j choosing candidate i .

Student i choosing answer j .

Player choosing move mj at chess.

Page 4: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess and Natural Laws

Logistic Laws.https://rjlipton.wordpress.com/2012/03/30/when-is-a-law-natural/

The Win-Expectation Curve:https://rjlipton.wordpress.com/2016/12/08/magnus-and-the-turkey-grinder/

Relative Perception of Value:https://rjlipton.wordpress.com/2016/11/30/when-data-serves-turkey/

Predictive Analytics: Inferring the probabilities pj of various eventsj :

Risk or damage events.

Voter j choosing candidate i .

Student i choosing answer j .

Player choosing move mj at chess.

Page 5: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess and Natural Laws

Logistic Laws.https://rjlipton.wordpress.com/2012/03/30/when-is-a-law-natural/

The Win-Expectation Curve:https://rjlipton.wordpress.com/2016/12/08/magnus-and-the-turkey-grinder/

Relative Perception of Value:https://rjlipton.wordpress.com/2016/11/30/when-data-serves-turkey/

Predictive Analytics: Inferring the probabilities pj of various eventsj :

Risk or damage events.

Voter j choosing candidate i .

Student i choosing answer j .

Player choosing move mj at chess.

Page 6: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess and Natural Laws

Logistic Laws.https://rjlipton.wordpress.com/2012/03/30/when-is-a-law-natural/

The Win-Expectation Curve:https://rjlipton.wordpress.com/2016/12/08/magnus-and-the-turkey-grinder/

Relative Perception of Value:https://rjlipton.wordpress.com/2016/11/30/when-data-serves-turkey/

Predictive Analytics: Inferring the probabilities pj of various eventsj :

Risk or damage events.

Voter j choosing candidate i .

Student i choosing answer j .

Player choosing move mj at chess.

Page 7: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess and Tests

Page 8: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Multinomial Logit Model

Given options m1; : : : ;mJ and information X = X1; : : : ;XJ about all ofthem, and characteristics S of a person choosing among them, we wantto project the probabilities pj of mj being chosen.

First de�ne numbersuj = g(X ;S)j often thought of as �utilities.� Then the multinomial

logit (MNL) model represents the probabilities via

log(pj ) = �+ �uj :

The quantitiesLj = e�+�uj

are called likelihoods. Then the probabilities are obtained simply bynormalizing them:

pj =LjPJ

j 0=1 Lj 0

=def softmax(�u1; : : : ; �uJ ):

Finally obtain � by �tting; e� becomes a constant of proportionality sothat the pj sum to 1.

Page 9: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Multinomial Logit Model

Given options m1; : : : ;mJ and information X = X1; : : : ;XJ about all ofthem, and characteristics S of a person choosing among them, we wantto project the probabilities pj of mj being chosen. First de�ne numbersuj = g(X ;S)j often thought of as �utilities.�

Then the multinomial

logit (MNL) model represents the probabilities via

log(pj ) = �+ �uj :

The quantitiesLj = e�+�uj

are called likelihoods. Then the probabilities are obtained simply bynormalizing them:

pj =LjPJ

j 0=1 Lj 0

=def softmax(�u1; : : : ; �uJ ):

Finally obtain � by �tting; e� becomes a constant of proportionality sothat the pj sum to 1.

Page 10: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Multinomial Logit Model

Given options m1; : : : ;mJ and information X = X1; : : : ;XJ about all ofthem, and characteristics S of a person choosing among them, we wantto project the probabilities pj of mj being chosen. First de�ne numbersuj = g(X ;S)j often thought of as �utilities.� Then the multinomial

logit (MNL) model represents the probabilities via

log(pj ) = �+ �uj :

The quantitiesLj = e�+�uj

are called likelihoods. Then the probabilities are obtained simply bynormalizing them:

pj =LjPJ

j 0=1 Lj 0

=def softmax(�u1; : : : ; �uJ ):

Finally obtain � by �tting; e� becomes a constant of proportionality sothat the pj sum to 1.

Page 11: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Multinomial Logit Model

Given options m1; : : : ;mJ and information X = X1; : : : ;XJ about all ofthem, and characteristics S of a person choosing among them, we wantto project the probabilities pj of mj being chosen. First de�ne numbersuj = g(X ;S)j often thought of as �utilities.� Then the multinomial

logit (MNL) model represents the probabilities via

log(pj ) = �+ �uj :

The quantitiesLj = e�+�uj

are called likelihoods.

Then the probabilities are obtained simply bynormalizing them:

pj =LjPJ

j 0=1 Lj 0

=def softmax(�u1; : : : ; �uJ ):

Finally obtain � by �tting; e� becomes a constant of proportionality sothat the pj sum to 1.

Page 12: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Multinomial Logit Model

Given options m1; : : : ;mJ and information X = X1; : : : ;XJ about all ofthem, and characteristics S of a person choosing among them, we wantto project the probabilities pj of mj being chosen. First de�ne numbersuj = g(X ;S)j often thought of as �utilities.� Then the multinomial

logit (MNL) model represents the probabilities via

log(pj ) = �+ �uj :

The quantitiesLj = e�+�uj

are called likelihoods. Then the probabilities are obtained simply bynormalizing them:

pj =LjPJ

j 0=1 Lj 0

=def softmax(�u1; : : : ; �uJ ):

Finally obtain � by �tting; e� becomes a constant of proportionality sothat the pj sum to 1.

Page 13: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Multinomial Logit Model

Given options m1; : : : ;mJ and information X = X1; : : : ;XJ about all ofthem, and characteristics S of a person choosing among them, we wantto project the probabilities pj of mj being chosen. First de�ne numbersuj = g(X ;S)j often thought of as �utilities.� Then the multinomial

logit (MNL) model represents the probabilities via

log(pj ) = �+ �uj :

The quantitiesLj = e�+�uj

are called likelihoods. Then the probabilities are obtained simply bynormalizing them:

pj =LjPJ

j 0=1 Lj 0

=def softmax(�u1; : : : ; �uJ ):

Finally obtain � by �tting; e� becomes a constant of proportionality sothat the pj sum to 1.

Page 14: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 15: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 16: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 17: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 18: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 19: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 20: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 21: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 22: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 23: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before.

Taking log(pj )� log(p1) on LHS gives same model.

Page 24: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Chess Decision Setting

One player P with characteristics S .

Multiple game turns t , each has possible moves mt ;j .

For a given turn (i.e., chess position) t , legal moves arem1; : : : ;mj ; : : : ;mJ (index t understood).

Moves indexed by values v1; : : : ; vJ in nonincreasing order.

Values determined by strong chess programs. Not apprehendedfully by P (bounded rationality, fallible agents).

Raw utilities uj = �(v1; vj ) by some di�erence-in-value function � ineither �pawn units� or �chance of winning� units.

Parameter � treated as a divisor s of those units, i.e., � = 1

s.

Second parameter c allows nonlinearity: �(v1; vi )c . (First c = 1.)

MNL model (called �Shares� by me) then equivalent to:

log(pj ) = Uj =

��(v1; vj )

s

�c

and we go as before. Taking log(pj )� log(p1) on LHS gives same model.

Page 25: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Alternative �Loglog-Linear� Model

Represent a di�erence in double logs of probabilities on left-hand sideinstead.

Now nice to keep signs nonnegative by inverting probabilities.

log log(1=pj )� log log(1=p1) = �Uj

The � can be absorbed as (1s)c even when c 6= 1 so my nonlinearized

utility still �ts the setting. Then abstractly:

log(1=pj )

log(1=p1)= exp(�Uj ) =def Lj

log(1=pj ) = log(1=p1)Lj

log(pj ) = log(p1)Lj

pj = pLj

1:

Analogy to power decay, Zipf's Law. . .Proceed to demo.

Page 26: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Alternative �Loglog-Linear� Model

Represent a di�erence in double logs of probabilities on left-hand sideinstead. Now nice to keep signs nonnegative by inverting probabilities.

log log(1=pj )� log log(1=p1) = �Uj

The � can be absorbed as (1s)c even when c 6= 1 so my nonlinearized

utility still �ts the setting. Then abstractly:

log(1=pj )

log(1=p1)= exp(�Uj ) =def Lj

log(1=pj ) = log(1=p1)Lj

log(pj ) = log(p1)Lj

pj = pLj

1:

Analogy to power decay, Zipf's Law. . .Proceed to demo.

Page 27: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Alternative �Loglog-Linear� Model

Represent a di�erence in double logs of probabilities on left-hand sideinstead. Now nice to keep signs nonnegative by inverting probabilities.

log log(1=pj )� log log(1=p1) = �Uj

The � can be absorbed as (1s)c even when c 6= 1 so my nonlinearized

utility still �ts the setting.

Then abstractly:

log(1=pj )

log(1=p1)= exp(�Uj ) =def Lj

log(1=pj ) = log(1=p1)Lj

log(pj ) = log(p1)Lj

pj = pLj

1:

Analogy to power decay, Zipf's Law. . .Proceed to demo.

Page 28: Chess and Natural Laws - cse.buffalo.edu · Kenneth W. Regan 1 University at Bu alo (SUNY) UB CSE 501, 11/13/2018 Password: Vicki Hanson 1 Joint work with amalT anTu Biswas and with

Chess and �Natural Laws�

Alternative �Loglog-Linear� Model

Represent a di�erence in double logs of probabilities on left-hand sideinstead. Now nice to keep signs nonnegative by inverting probabilities.

log log(1=pj )� log log(1=p1) = �Uj

The � can be absorbed as (1s)c even when c 6= 1 so my nonlinearized

utility still �ts the setting. Then abstractly:

log(1=pj )

log(1=p1)= exp(�Uj ) =def Lj

log(1=pj ) = log(1=p1)Lj

log(pj ) = log(p1)Lj

pj = pLj

1:

Analogy to power decay, Zipf's Law. . .Proceed to demo.