Seminar on Patterns of Thought-1.odp

68
 Pattern Theory  Presentation By Sahar Pirmoradian  Adapted from Ulf Grenander , Brown University

Transcript of Seminar on Patterns of Thought-1.odp

Page 1: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 1/68

 

Pattern Theory

 Presentation By Sahar Pirmoradian

 Adapted from Ulf Grenander, Brown University

Page 2: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 2/68

 

Pattern Theory

Not Pattern Recognition Not just classifying objects

 A mathematical formalism, A pattern Algebra reconstructing the processes and events that

produced real structures

The genesis of the observation = Transformationof some ideal images using various

transformations

Page 3: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 3/68

 

Generators

Building blocks Generating observed signal

Denoted by g

Generator Space: G The set of all generators

Page 4: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 4/68

 

Similarity Group

To represent symmetries and invariance 

of patterns: Similarity Group S (Group of Transformations)

s: elements of this group

s is a bijective mapping:

g1and g

2are similar IF there exists a similarity s 

such that g2= sg

1

GG s ↔:

Page 5: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 5/68

 

Bonds

To build larger structures:

Generators’ interfaces: Bonds (b) In the example: b1, b2, b3, b4, b5 

Page 6: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 6/68

 

Bonds

 Arity (ω(g)), the number of bonds of generator g In the example: ω (g)= 5

ωin (g) = 2

ωout (g) = 3

Page 7: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 7/68

 

Bonds

bond value (β): Assigned to each bond

In the example:{β1, β2, β3, β4, β5}

IMPORTANT IN COMBINATION OF GENERATORS

Page 8: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 8/68

 

Bonds

Bond Structure is S-invariant:

If g1 and g2are similar => they have the same bond

structure

Bond Value is not S-invariant.

Page 9: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 9/68

 

Configurations 

Generators ~ Atoms

Configurations ~ Molecules

Page 10: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 10/68

 

Configuration Diagram

Configuration c = σ(g1, … g5)

Internal bonds: connected bonds External bonds

Page 11: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 11/68

 

Bond Value Relation

In a connector graph σ ρ : Bond value relation

ρ:Bv X Bv -> {True, False}

Bv: set of bond values

IF ρ (βi, β j)= True => Pair (βi, β j) is REGULAR. IF ρ (βi, β j)=False => Pair (βi, β j) is IRREGULAR.

Page 12: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 12/68

 

Connection Type

Connection type: Σ 

The family of connector  graphs σ(g1, … gn)

Σ = LINEAR

Σ = TREE

Σ = LATTICE

Page 13: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 13/68

 

Regularity

 A Configuration c is: Locally regular  

If all ρ of internal bonds are true

Globally regular   

If c is both Locally & Globally regular => c is Regular 

Σ∈σ 

Page 14: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 14/68

 

Configuration Space

C(R): configuration space

The set of all Regular Configurations Where R=<G, S, ρ, Σ >

Referred to as a Regularity

Page 15: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 15/68

 

Probabilities

ρ is binary 

We should define:   A continuum valued function

Acceptor Function,  A(.,.) on B x B, non-negative real value

Q(.), non-negative weight function

Making probabilities depend on generatorsthemselves

Z: partition function 

Page 16: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 16/68

 

Probability

The probability of configuration c with the

connector graph σ(g1, … gn)

∏ ∏′′=i

ii ji j g Q g  g  A Z 

c p )())(),((1

)( β β 

∑ =

c

c p 1)(

Page 17: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 17/68

 

Energy

E: interaction energy

T: temperature, positive constant

)],(1

exp[),( β β β β  ′−=′ E T 

 A

Page 18: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 18/68

 

Patterns of Thought

 An application of Pattern Theory

Page 19: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 19/68

 

Patterns of Thought

Generators: physical things, non-physical

things, events

felineM

inanimateanimate

humanMcanineFcanineMfemaleF humanF vehiclefurniture

catM,

Felix

catF,

Mosan

dogF,

Rufsan

dogM,

Rufus

man,

 boy,

John

woman,

girl,

Joan

car,

 bicycle

table,

disk 

M = male

F = female

Env(MIND)

felineM

inanimateanimate

humanMcanineFcanineMfemaleF humanF vehiclefurniture

catM,

Felix

catF,

Mosan

dogF,

Rufsan

dogM,

Rufus

man,

 boy,

John

woman,

girl,

Joan

car,

 bicycle

table,

disk 

M = male

F = female

Env(MIND)

Page 20: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 20/68

 

Modality

G is partitioned into subsets: Modalities

Color, Movement, …

Page 21: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 21/68

 

ModalityANIMATE

FLORAHUMAN

ANIMAL

HUMANm HUMANf  

HUMANmy

LEVEL=1

ARITY=0

HUMANma

LEVEL=1

ARITY=0

HUMANfy

LEVEL=1

ARITY=0

HUMANfa

LEVEL=1

ARITY=0

 boy, Bob,

Jim, Peter,

Robbie,

Richard, Tom

self, man,

David, Bert,

Donald,

visitor,

stranger 

girl,Ann,

Mary, Syd,

Linda,

Helen,

Sarah,

Monica

woman,

Carin,

Lisbeth,

Eve,

Ruth

FLOWER 

LEVEL=1

ARITY=0

dog,

 puppy,

Rufsan,

Rufus,

Spot,

smokey

ANIMAL

CANINE

LEVEL=1

ARITY=0

flower,

rose, tulip,

flowerstem,

flowerleaf,

ANIMATE

FLORAHUMAN

ANIMAL

HUMANm HUMANf  

HUMANmy

LEVEL=1

ARITY=0

HUMANma

LEVEL=1

ARITY=0

HUMANfy

LEVEL=1

ARITY=0

HUMANfa

LEVEL=1

ARITY=0

 boy, Bob,

Jim, Peter,

Robbie,

Richard, Tom

self, man,

David, Bert,

Donald,

visitor,

stranger 

girl,Ann,

Mary, Syd,

Linda,

Helen,

Sarah,

Monica

woman,

Carin,

Lisbeth,

Eve,

Ruth

FLOWER 

LEVEL=1

ARITY=0

dog,

 puppy,

Rufsan,

Rufus,

Spot,

smokey

ANIMAL

CANINE

LEVEL=1

ARITY=0

flower,

rose, tulip,

flowerstem,

flowerleaf,

Page 22: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 22/68

 

Thought

Configurations: Thoughts  Regular thoughts

Completely regular thoughts

MIND(R): The set of all (completely) regular 

thoughts

Page 23: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 23/68

 

Modality Group

Similarity Group: Modality Group

Generators in a same modality are similar 

Generators can be substituted

Page 24: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 24/68

 

Thought Pattern

 A subset is called a thought

pattern if it is invariant with respect to the

modality group S

)( R MIND P ⊂

Page 25: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 25/68

 

Thought Pattern

Example: Mary strokes the very happy cat

Page 26: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 26/68

 

Thought Pattern

Different Topologies of Thought Patterns

Page 27: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 27/68

 

Probabilities of Thought

Energy

Conscious thoughts, unconscious thoughts

∏σ∈′

′′∏=

κ 

=)k ,k (

)]ig( j b),ig( j b[T1A

n

1i)ig(Q)T(Z!n n)thought( p

∑∈′

′′∑=

−−−=

σ κ 

),(

)](),([

1

1)()log()!log()(

k k i g  jbi g  jba

n

i

T i g qn

nthought  E 

Page 28: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 28/68

 

Mental Dynamics

Simple Moves: Add a new generator 

Delete a generator and its connections

Delete a connection

Create a connection

Replace a generator by another generator 

 

Page 29: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 29/68

 

Mental Dynamics

Replace

Page 30: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 30/68

 

Composite Moves

Delete + Replace

Page 31: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 31/68

 

 ABSTRACTION If a thought occurs more than occasionally:

thought = (married ↓humanM and humanF(

g = marriage

Page 32: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 32/68

 

SIMILARITY

Page 33: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 33/68

 

COMPOSITION

Page 34: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 34/68

 

MUTATION

Page 35: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 35/68

 

CROSSOVER

Page 36: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 36/68

 

SPECIALAZION

Page 37: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 37/68

 

Generalization

MOD(bark↓Rufus) = (animal_sound↓animalM)

)(thought: thought  MOD→

Page 38: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 38/68

 

Mind Development (memory)

 1remember Q(g);remember Q(g) QQ >×=

 1forgetQ(g);forgetQ(g) QQ <×=

Page 39: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 39/68

 

Living alone

Without any Input

Page 40: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 40/68

 

Data Structure

Page 41: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 41/68

 

Data Structure - Example

Page 42: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 42/68

 

Themes of a person suffering from

schizotypal personality disorder:

Ideas of reference

Magical thinking

Unusual perceptualexperience

Eccentric behavior 

Odd speech

Paranoid ideation

No close friend

Constricted affect

Social anxiety

Page 43: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 43/68

 

Flow chart

start

end

Time?

thinking1

thinking2 thinking3

no

yesRemembrance

Changing

Theme

Page 44: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 44/68

 

Thinking1

1. Think3.m

2.  Add generators in L3

3. Show conscious thought4. Save top_3_ideas and top_2_ideas

5. Update memory

6. Show idea

Page 45: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 45/68

 

Thinking2

1. Composite moves (composite_moves1.m)

2. Connect open down bonds

3.  Add generators in L3

4. Show conscious thought

5. Save top_3_ideas and top_2_ideas

6. Update memory

7. Show idea 

Page 46: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 46/68

 

Thinking3

1. Composite moves (composite_moves2.m)

2. Connect open down bonds

3.  Add generators in L3

4. Show conscious thought

5. Save top_3_ideas and top_2_ideas

6. Update memory

7. Show idea 

Page 47: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 47/68

 

Think3

Think3.m Content = build_thought_2.m

 Add_generator_new.m

connecting down bonds Find_open_down_bond.m

Connect_down_bond.m

Page 48: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 48/68

 

Composite-move1

add_generator_up_Q(content,connector,theme);

add_generator_new(content,connector,Q_theme);

delete_generator_connections_2(content,connector)

add_generator_up_Q(content,connector,theme);

delete_generator_connections_2(content,connector)

delete_generator_connections_2(content,connector)

Page 49: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 49/68

 

Composite-move2

delete_generator_connections_2(content,connector); add_generator_up_Q(content,connector,theme); add_generator_new(content,connector,Q_theme); add_generator_up_Q(content,connector,theme);

add_generator_up_Q(content,connector,theme); delete_generator_connections_2(content,connector); delete_generator_connections_2(content,connector); add_generator_up_Q(content,connector,theme); delete_generator_connections_2(content,connector);

Page 50: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 50/68

 

Build_thought_2

build_thought_2.m: Select a random theme

Select related modalities to the theme

Select related generators to the modalities Set Q(g) = 20 else Q=1

Selecting generators in different levels: With a high probability just one of generators in level 1 is

selected.

More than one, with same probability are selected Probability of generators in level4 is zero!

Content =1 626

2 26

3 433

Backgammon (modality: Plays )

Dance (modality: Move)

Lose (modality: Outcome)

Page 51: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 51/68

 

Add_generator_new

 Add_generator_new.m Select a generator regarding Q

Probability of adding the selected generator g:

(mu=2) P = mu/(n+1) * Q(g)

P = p / (p+1)

If select (p, 1-p) == 1 then add g to content

Page 52: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 52/68

 

Find_open_down_bond

Find_open_down_bond.m Returning found = 1 if there’s still a generator not

connected

Returning the unconnected generator 

Page 53: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 53/68

 

Connect_down_bond

Connect_down_bond.m: Find all of generators may be connected to the

unconnected generator 

Finding the modality of the g Finding the acceptable modalities for down bond

connection of the g

Finding all the generators of the acceptable modalities

Search the acceptable generators in the mind

Page 54: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 54/68

 

Connect_down_bond

Connect_down_bond.m: Probability of selection for connecting to down bond:

Select(prob1, prob2, ...)

Prob_i=Q(v(nu))*n/(n+1)*A(g,v(nu))^(1/T) T=1

g: the open down bond generator 

v(nu): acceptable generators in the mind (in the lower level

of g)

Page 55: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 55/68

 

Connect_down_bond

Connect_down_bond.m If not valid generator in mind or already a

connector between the generator and the

selected generator, a valid generator is connectedto the content with probability: Prob_i=Q(v(nu))*n/(n+1)*A(g,v(nu))^(1/T)

in adding a related generator to the mind there'snot any condition. the mind can think 'bert buy bert ring'.

Page 56: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 56/68

 

Get_top_2ideas

Get_top_2ideas.m Finding top generators in level 2

Finding the downward connectors from the top to

find the connected generators in level 1 Comparing omega of the top and the number of 

connected generators to it

Page 57: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 57/68

 

Add_generator_up_Q

 Add_generator_up_Q: Selecting randomly one of generators in content Finding valid generators to be connected upward

to the selected generator, regardless of mind Computing the probability of each valid generator 

based on their Qs and As. Connecting two selected generators with each

other on the valid omega.

Delete generator connection

Page 58: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 58/68

 

Delete_generator_connection_ 

2

Delete_generator_connection_2: If connector is empty, delete first member of 

content with the probability: (mu = 2)

g = content(1,2)  prob_del=(n/mu)/Q(g); %check this!

prob_del=prob_del/(1+prob_del);

if select([prob_del,1-prob_del]), delete, end

 All the downward and upward connections from

the content(1,2) will be found

D l t t ti 2

Page 59: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 59/68

 

Delete_generator_connection_2:

The generator and all the connected generators

-gk- be deleted with the probability: p=n/(mu*Q(g)) * multiply(A(g,gk)^(-1/T))

p = p/p+1 Select(p,1-p)

 A is greater -> the probability of delete is more less

Page 60: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 60/68

 

Appendix

Page 61: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 61/68

 

Symmetry Group

Symmetry = Rotation & Reflection

Elements: id, r1, r2, r3, fv, fh, fd, fc

Page 62: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 62/68

 

Symmetry Group

1. Closure

2.  Associativity

3. Identity Element

4. Inverse Element

Page 63: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 63/68

 

Bijective Function

bijective function is a function f from a set X  

to a set Y with the property that, for every y in

Y , there is exactly one x in X such that

f ( x ) = y .

Page 64: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 64/68

 

Permutation Group

permutation group is a group G whose

elements are permutations of a given set M ,

and whose group operation is the

composition of permutations in G (which arethought of as bijective functions from the set

M to itself);

Page 65: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 65/68

 

Permutation Group- Sample

e = (1)(2)(3)(4) This is the identity, the trivial permutation which fixes each

element. a = (1 2)(3)(4) = (1 2)

This permutation interchanges 1 and 2, and fixes 3 and 4. b = (1)(2)(3 4) = (3 4) Like the previous one, but exchanging 3 and 4, and fixing the

others. ab = (1 2)(3 4)

This permutation, which is the composition of the previous two,exchanges simultaneously 1 with 2, and 3 with 4.

Page 66: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 66/68

 

Permutation Group

the relationship is often written as (G,M ).

Note that the group of all permutations of a

set is the symmetric group; the term

 permutation group is usually restricted tomean a subgroup of the symmetric group.

The symmetric group of n elements is

denoted by Sn.

Page 67: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 67/68

 

Euclidean Space

 A Sample of Euclidean Space: the sum of the angles in a triangle is always 180

degrees.

The surface of a sphere is not a EuclideanSpace: The sum of the angles of a triangle on a sphere is

greater than 180.

Page 68: Seminar on Patterns of Thought-1.odp

7/27/2019 Seminar on Patterns of Thought-1.odp

http://slidepdf.com/reader/full/seminar-on-patterns-of-thought-1odp 68/68

Euclidean Space

There is only one Euclidean space of each

dimension.

While there are many non-Euclidean spaces

of each dimension.