20
DOCUMENT RESUME ED 472 095 SE 066 382 AUTHOR Labelle, Gilbert TITLE Manipulating Combinatorial Structures. PUB DATE 2000-00-00 NOTE 18p.; In: Canadian Mathematics Education Study Group = Groupe Canadien d'Etude en Didactique des Mathematiques. Proceedings of the Annual Meeting (24th, Montreal, Quebec, Canada, May 26-30, 2000); see SE 066 379. PUB TYPE Guides Non-Classroom (055) -- Speeches/Meeting Papers (150) EDRS PRICE EDRS Price MF01/PC01 Plus Postage. DESCRIPTORS Curriculum Development; Higher Education; Interdisciplinary Approach; Mathematical Applications; *Mathematical Formulas; Mathematical Models; *Mathematics Instruction; Modern Mathematics; Teaching Methods IDENTIFIERS Combinatorics ABSTRACT This set of transparencies shows how the manipulation of combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities at every level of education from elementary school to university. The transparencies describe: (1) the importance and relations of combinatorics to science and social activities; (2) how analytic/algebraic combinatorics is similar to analytic/algebraic geometry; (3) basic combinatorial structures with terminology; (4) species of structures; (5) power series associated with any species of structures; (6) similarity of operations between power series and the corresponding species of structures; (7) examples illustrating where the structures are manipulated; and (8) general teaching/learning activities. (KHR) Reproductions supplied by EDRS are the best that can be made from the original document.

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Page 1: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

DOCUMENT RESUME

ED 472 095 SE 066 382

AUTHOR Labelle, Gilbert

TITLE Manipulating Combinatorial Structures.

PUB DATE 2000-00-00

NOTE 18p.; In: Canadian Mathematics Education Study Group = GroupeCanadien d'Etude en Didactique des Mathematiques. Proceedingsof the Annual Meeting (24th, Montreal, Quebec, Canada, May26-30, 2000); see SE 066 379.

PUB TYPE Guides Non-Classroom (055) -- Speeches/Meeting Papers (150)

EDRS PRICE EDRS Price MF01/PC01 Plus Postage.

DESCRIPTORS Curriculum Development; Higher Education; InterdisciplinaryApproach; Mathematical Applications; *Mathematical Formulas;Mathematical Models; *Mathematics Instruction; ModernMathematics; Teaching Methods

IDENTIFIERS Combinatorics

ABSTRACT

This set of transparencies shows how the manipulation ofcombinatorial structures in the context of modern combinatorics can easilylead to interesting teaching and learning activities at every level ofeducation from elementary school to university. The transparencies describe:(1) the importance and relations of combinatorics to science and socialactivities; (2) how analytic/algebraic combinatorics is similar toanalytic/algebraic geometry; (3) basic combinatorial structures withterminology; (4) species of structures; (5) power series associated with anyspecies of structures; (6) similarity of operations between power series andthe corresponding species of structures; (7) examples illustrating where thestructures are manipulated; and (8) general teaching/learning activities.(KHR)

Reproductions supplied by EDRS are the best that can be madefrom the original document.

Page 2: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

O

PERMISSION TO REPRODUCE ANDDISSEMINATE THIS MATERIAL HAS

BEEN GRANTED BY

1

TO THETHE EDUCATIONAL RESOURCESINFORMATION CENTER (ERIC)

U.S. DEPARTMENT OF EDUCATIONOffice of Educational Research and Improvement

EDUCATIONAL RESOURCES INFORMATIONCENTER (ERIC)

This document has been reproduced asreceived from the person or organizationoriginating it.

Minor changes have been made toimprove reproduction quality.

Points of view or opinions stated in thisdocument do not necessarily representofficial OERI position cr policy.

Manipulating Combinatorial Structures

Gilbert LabelleUniversite du Quebec a Montreal (UQAM)

A combinatorial structure is a finite construction made on a finite set of elements. In real-lifesituations, combinatorial structures often arise as "skeletons" or "schematic descriptions"of concrete objects. For example, on a road map, the elements can be cities and the finiteconstruction can be the various roads joining these cities. Similarly, a diamond can be con-sidered as a combinatorial structure: the plane facets of the diamond are connected togetheraccording to certain rules.

Combinatorics can be defined as the mathematical analysis, classification and enu-meration of combinatorial structures. The main purpose of my presentation is to show howthe manipulation of combinatorial structures, in the context of modern combinatorics, caneasily lead to interesting teaching/learning activities at every level of education: from el-ementary school to university.

The following pages of these proceedings contain a grayscale version of my (color)transparencies (two transparencies on each page). I decided to publish directly my trans-parencies (instead of a standard typed text) for two main reasons: my talk contained a greatamount of figures, which had to be reproduced anyway, and the short sentences in thetransparencies are easy to read and put emphasis on the main points I wanted to stress.

The first two transparencies are preliminary ones and schematically describe: a) theimportance and relations of combinatorics with science/ social activities, b) how analytic/algebraic combinatorics is similar to analytic/ algebraic geometry. The next 7 transparencies(numbered 1 to 7) contain drawings showing basic combinatorial structures together withsome terminology. Collecting together similar combinatorial structures give rise to the con-cept of species of structures (transparencies 8 to 12). A power series is then associated to anyspecies of structures enabling one to count its structures (transparencies 13 to 15). Each op-eration on power series (sum, product, substitution, derivation) is reflected by similar opera-tions on the corresponding species of structures (transparencies 16 to 18). The power of thiscorrespondence is illustrated on explicit examples (transparencies 18 to 26) where the struc-tures are manipulated (and counted) using various combinatorial operations. Transparen-cies 27 to 30 suggest some general teaching/ learning activities (from elementary to advancedlevels) that may arise from these ideas. I hope that the readers will agree that manipulatingcombinatorial structures constitutes a good activity to develop the mathematical mind.

References

The main references for the theory of combinatorial species are:

Joyal, A. (1981). Une theorie combinatoire des series formelles, Advances in Mathematics, 42, 1-82.Bergeron, F., Labelle, G., & Leroux, P. (1998). Combinatorial Species and Tree-like Structures.

Encyclopedia of Math. and its Applications, Vol. 67, Cambridge University Press.

BEST COPY AVAILABLE

2 3

Page 3: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

PR

ELI

MIN

AR

IES

The

dyn

amic

con

nect

ions

bet

wee

n

com

bina

toria

l / d

iscr

ete

scie

nce

I soc

ial

mat

hem

atic

san

dac

tiviti

es

will

gre

atly

incr

ease

dur

ing

the

com

ing

deca

des

:

Com

pute

r sc

ienc

e(a

naly

sis

of a

lgor

ithm

s. o

rgan

izat

ion

and

com

pres

sion

of d

ata

stru

ctur

es, e

tc)

Che

mis

try

(cla

ssifi

catio

n. s

ymm

etrie

s of

mol

ecul

es,

isom

ers.

etc

)

Com

bina

toric

s

Phy

sics

(cla

ssifi

catio

n, s

ymm

etrie

s of

ato

ms,

quan

tum

theo

ry. F

eynm

an in

tegr

als.

etc

)

Bio

logy

(ana

lysi

s of

DN

A, g

enet

ic c

ode.

clas

sific

atio

n of

spe

cies

, etc

)

Mat

hem

atic

s(a

naly

sis,

cal

culu

s, a

lgeb

ra, g

eom

etry

,gr

aphs

, gro

ups,

etc

)

Hum

an a

ctiv

ities

(pub

lic k

eys

met

hods

of e

ncry

ptio

n,en

codi

ng o

f com

pact

dis

cs.

secu

re tr

ansa

ctio

ns, c

omm

unic

atio

ns.

desi

gn o

f pla

ne fl

ight

s, s

hort

est p

aths

.te

achi

ng a

nd le

arni

ngba

sic

com

bina

toria

l stu

ctur

es. e

tc)

AN

ALY

TIC

/ A

LGE

BR

AIC

GE

OM

ET

RY

Geo

met

rical

-4M

athe

mat

ical

figur

esfo

rmul

as

02x

- e

y +

7 =

0

x2 +y2

= 9

y=e2

AN

ALY

TIC

/ A

LGE

BR

AIC

CO

MB

INA

TO

RIC

S

Com

bina

toria

l--

->M

athe

mat

ical

stru

ctur

es4-

-fo

rmul

as

0Y

=1"

*()

y =

x +

xy2

e3x

Page 4: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

12

MA

NIP

ULA

TIN

G C

OM

BIN

AT

OR

IAL

ST

RU

CT

UR

ES

Gilb

ert L

abel

le /

LaC

IM -

UQ

AM

In C

ombi

nato

rics,

a s

truc

ture

, s, i

sa

finite

con

stru

ctio

nm

ade

on a

fini

te s

et U

.

We

say

that

: U

Is th

e un

derly

ing

set o

fs

or: U

is e

quip

ped

with

(th

e st

ruct

ure)

sor

: s is

(bu

ilt)

on U

or: s

is la

belle

d by

the

set U

Exa

mpl

e 1.

A tr

ee o

n tJ

=a,

b, c

,,

+

el"

kit

"1:\6

cif

JR

ay

Exa

mpl

e 2. 4

A r

oote

d tr

ee o

n 1.

7..k

bc,..

x,rt

+3

e

1,4

3 a

a.

4

Exa

mpl

e 3.

An

orie

nted

cyc

le o

n II

f,

936

IA

SP

'kcL

-.1

(4...

;.7

3V

aria

nts:

even

(or

ient

ed)

cycl

eod

d (o

rien

ted)

cyc

le

Exa

mpl

e 4.

A s

ubse

t on

(of)

tro

1%.f

f.,

(or

bico

lora

tion)

0_L

0

Page 5: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

34

Exa

mpl

e 5.

A (

the)

set

str

uctu

re o

nE

xam

ple

8.A

par

titio

n on

= 1

0,*,

42,

3, 4

, (7,

'1'3

1:1

U /,

0AA

J- TJJ1 Var

iant

s:ev

en s

etod

d se

t

Exa

mpl

e 6.

A p

erm

utat

ion

onLY

-=Ii

2/30

0 /6

, ai b

d

ys..,

.ITt

.egk

tN,

.".`

tf

ts

. \--i

i.el

;0U

',.,

..*

.11

.-1N

e4

r )%/

' I;

/\-

- 4.

a6

i ---

>...

. f

Exa

mpl

e 7.

Alin

ear

orde

r on

U=

1=d

Al;

.40;

a3

er xs44

.

Exa

mpl

e 9.

An

endo

func

tion

on62

-3g,

aS

e34

V24

1g1 1-

3 e

2}ri

Vr.

.v,.

ea9

NN a

S.

H.

Of

fjR

io63

1S

y

r17.

-43"

4

Iffa

r.v.

../6

2(iv

itvy

'IVts

,62,

44,

Soc

/4 I

ti,.4

7I

17

0

2.,,

,..\,.

..0.,.

......

..0...

4".

Ft 3

s:-"

,3..,

..-er

-'-er

e...

a 3

2N

5?

SP

*3

Page 6: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

56

Exa

mpl

e 10

. A b

icol

ored

pol

ygon

on

TJ=

14,1

2,c,

d,e,

f3

Exa

mpl

e 11

.A

gra

ph o

n E

T=

it,

.. .

,fq

,,-r,

;--,

-:--

-7

0Z

S

/3,2

4,...

......

.___

#07

.t.,

11

N,

ir...

.,,,,,

,.....

..4T

4....

.1 -

..A

teip

23

9...

.Ie.

'11

-:1V

,,..

.....,

.---

2 9

r, fvS

-2

a.,

q5'

i..g

Exa

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e 12

. A c

onne

cted

gra

ph o

n U

=

ft'

i9n

"111

'

,00.

417

34/

6

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e 13

. A s

ingl

eton

on

U=

I A

l

a(T

here

is n

o si

ngle

ton

stru

ctur

e on

U if

(r.

.7(*

1.)

Exa

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e 14

.A

n em

pty

set s

truc

ture

on

U=

16

4:

(The

re is

no

empt

y se

t str

uctu

re if

T7*

+)

Exa

mpl

e 15

.A

n In

volu

tion

on U

=1*

-,4.

, A.

hh

A

rrn

s

4e

a.

ET

C, E

TC

, ET

C,

...

Page 7: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

78

CO

NV

EN

TIO

N :

An

arbi

trar

y st

ruct

ure

A. o

n T

...7

will

som

etim

es b

e re

pres

ente

dby

bc

Her

e, U

=5

Ad

6., c

., ,A

)e.

A s

truc

ture

A. o

n T

..7 is

said

to b

e ev

en (

odd)

if LT

con

tain

s an

eve

n(o

dd)

num

ber

of e

lem

ents

.

Tw

o st

ruct

ures

4, a

nd t

are

said

to b

e di

sjoi

nt

if th

eir

unde

rlyin

g se

ts a

redi

sjoi

nt.

Str

uctu

res

can

be s

tudi

edan

d cl

assi

fied

byco

llect

ing

them

into

SP

EC

IES

OF

ST

RU

CT

UR

ES

:

For

exam

ple,

we

can

cons

ider

the

spec

ies

ath

e sp

ecie

sA

the

spec

ies

the

spec

ies

ce.

the

spec

ies

a)th

e sp

ecie

sE

the

spec

ies

E *

van

the

spec

ies

Ew

ath

e sp

ecie

s S

the

spec

ies

L.th

e sp

ecie

s B

the

spec

ies

End

the

spec

ies

VI'

of a

llbi

colo

red

poly

gons

)th

e sp

ecie

s 21

4.0,

. of a

ll gr

aphs

,th

e sp

ecie

sof

all

conn

ecte

d gr

aphs

,

the

spec

ies

)(of

all

sing

leto

ns,

the

spec

ies

Iof

the

empt

y se

t,th

e em

pty

spec

ies

0(c

onta

inin

g no

str

uctu

re),

the

spec

ies

Inv

of a

llin

volu

tions

,

of a

ll tr

ees

(arb

res)

,

of a

ll ro

oted

tree

s(a

rbor

e5ce

nces

),

of a

ll cy

cles

,of

all

even

cyc

les,

of a

ll su

bset

s (o

f set

s),

of a

ll se

ts (

ense

mbl

es),

of a

ll ev

en s

ets,

of a

ll od

d se

ts,

of a

ll pe

rmut

atio

ns,

of a

ll lin

ear

orde

rs,

of a

ll pa

rtiti

ons,

of a

ll ed

ofun

ctio

ns,

the

spec

ies

Fof

all

F-

stru

ctur

es.

Page 8: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

910

By

conv

entio

n, fo

r an

y fin

ite s

et tJ

we

writ

e

FLU

]:=

the

set o

f all

F-st

ruct

ures

on

U

Exa

mpl

e.If

F =

= th

e sp

ecie

s of

cyc

les,

then

Is a

41-

str

uctu

re

and

if"i

f=

rn,n

,1,,

11, t

hen

Cif

rn, )

1, 0

)131

AN

DirO

Ar't

ger

e't

"&tli

von

;:74.

."44

4171

44,5

r3

32

Fun

dam

enta

l pro

pert

ies

satis

fied

byth

e pr

ocee

ding

exa

mpl

e :

PR

OP

ER

TY

1.

For

eve

ry fi

nite

set

t7, t

he s

et47

E73

Is a

lway

s fin

ite.

PR

OP

ER

TY

2.

Eve

ry b

iject

ion

U =

rn,

rij

PV11

1 I

V =

14-

ha

c, 4

3in

duce

s an

othe

r bi

ject

ion,

CL

U)

44>

446

411,

24."

I0,

1=1

whi

ch r

elab

els

via

/3 e

ach

C-s

truc

ture

on

Uto

form

a c

orre

spon

ding

C -

stru

ctur

e on

V.

Page 9: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

011

12

Not

e. T

wo

succ

essi

ve r

elab

ellin

gsvi

a A

and

Al

amou

nts

to a

sin

gle

rela

belli

ng v

ia A

'o /3

:

P4.)

flop

ou,

ctav

i )m

ei°

Cfp

le

cm=

CLA

."3

CD

DE

FIN

ITIO

N (

And

re J

oyal

,U

CIA

M,1

979)

A c

ombi

nato

rial s

peci

es is

aru

le F

whi

ch

1) g

ener

ates

, for

eac

h fin

ite s

etU

,an

othe

r fin

ite s

etF

LU),

2) g

ener

ates

, for

eac

h bi

ject

ion

FLU

)(3

*F

,an

othe

r bi

ject

ion

FE

V v)in

a c

oher

ent w

ay :

F[(

1° J

o Fr

iaj

F1(3

'0A

l

Any

a. I

n F

LU)

is c

alle

d a

F-s

truc

ture

on

U .

0 A

ny b

iject

ion

F [f

a] is

calle

d F

- re

labe

lling

via

p .

CO

NV

EN

TIO

N. A

n ar

bitr

ary

F -

stru

ctur

e A

L on

T..7

can

be r

epre

sent

edby

dia

gram

s lik

e

or

or

ET

C

Cou

ntin

g st

ruct

ures

of a

giv

ensp

ecie

s

The

pro

pert

ies

of r

elab

ellin

gsim

ply

that

the

num

ber

of F

-st

ruct

ures

on

t7de

pend

s on

ly o

n th

e nu

mbe

r of

elem

ents

of U

.

Tha

t is,

1 F

M I

depe

nds

only

on

l tj .

Page 10: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

1314

Hen

ce, i

f we

wan

t to

sim

ply

coun

t F -

stru

ctur

es,

it is

suf

ficie

nt to

con

side

r on

ly th

e ca

ses

1.7

= n

=--

1..#

2.11

3n

= 0

,1,

2o .

.

DE

FIN

ITIO

N.

Let F

be

a sp

ecie

s an

d

=IF

te_1

1=

num

ber

of F

-st

ruct

ures

labe

lled

by1,

2,...

,ni.

The

gen

erat

ing

serie

s of

the

spec

ies

F is

00

F(x)

-7,

&I

n!=

F(x

) =

s xv

in

Exa

mpl

e 1.

S t

the

spec

ies

of p

erm

utat

ions

S(x

) =

E p

i!=

Ex"

nvo

0,1*

0I

Exa

mpl

e 2.

6:1

% th

e sp

ecie

s of

sub

sets

2"eZ

Xn3

9

Exa

mpl

e 3.

Eth

e sp

ecie

s of

set

s

EC

zJ=

=ex

fly.

ww

Exa

mpl

e 4.

;th

e sp

ecie

s of

eve

n se

ts

(x)

++

De*

+.=

cos

hN

OT

E. W

e w

ill s

ee th

at g

ener

atin

g se

ries

give

ris

eE

wen

to a

dyn

amic

con

nect

ion

betw

een

CO

MB

INA

TO

RIC

S a

nd A

NA

LYS

IS.

Exa

mpl

e 5.

Eye

dt

the

spec

ies

of o

dd s

ets

(1)=

+13

1-+

+ -

-=

sinl

nx

Page 11: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

1516

Exa

mpl

e 6.

L th

e sp

ecie

s of

line

ar o

rder

s

L (

x) z

x"

Ex"

111.

.ePl

Exa

mpl

e 7.

C ;

the

spec

ies

of c

ycle

s

C(x

)=

E X

" =

.0/n

(1%

ve,

)n

It I

Exa

mpl

e 8.

the

spec

ies

of e

ven

cycl

esIS

MS

c.(x

)= D

n.-0

14 m

zak

ir aq

nft

PI e

ven

itit,

I

Exa

mpl

e 9.

End

= th

e sp

ecie

s of

end

ofun

ctio

ns

End

(X

) -=

n"-F

rP1

3o

Exa

mpl

e 10

.X

:th

e sp

ecie

s of

sin

glet

ons

X(4

) =

++

Coi

fs=

Exa

mpl

e 11

.ith

m I

the

spec

ies

of g

raph

s

CZ

)"

Tc/

el a

CO

MB

ININ

G a

nd M

AN

IPU

LAT

ING

SP

EC

IES

We

know

how

toad

d, m

ultip

ly, s

ubst

itute

, and

diff

eren

tiate

serie

s to

obt

ain

othe

r se

ries

:

IfF

(x).

. Eib

.lir

kG

(30-E

i p, 24+

1.1

,,,,

INN

,

H (

x) =

Z 1

7.,

Inv

then

we

have

the

follo

win

g ta

ble

and OP

ER

AT

ION

CO

EF

FIC

IEN

T h

n

H(4

= F

(x)

+G

(x)

il =

5 +

5;,

1-1W

= F

(c)

- 6(

%)

4_10

1 ii.

h=as

-*

ti(7)

=F

(6(

2))

G(o

)= ie

r 0

=7"

,81

,ni

t6

...St

ink

3-4

4A"I

.

H (

x) =

ti-

F(x

)h

= 5

+,

Thi

s ta

ble

sugg

ests

cor

resp

ondi

ngco

mbi

nato

rial o

pera

tions

for

spec

ies

:

Page 12: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

1718

DE

FIN

ITIO

N. F

rom

giv

en s

peci

es F

and

Got

her

spec

ies

can

be b

uilt

:

The

e4p

ecie

s F

+G

A (

F+

G)-

stru

ctur

esE

r(4

1.44

..tG

oph.

)

a 6-

stru

ctur

e

a F

-str

uctu

re

or

t\..)

The

spe

cies

Gan

ord

ered

pai

r

A (

F-G

)-

stru

ctur

e is

of a

F-s

truc

ture

and

aci

lsjo

irrt 6

-str

uctu

re

The

spe

cies

F(G

) =

Fo

Ga

F.-

stru

ctur

eA

(F

o G

)-st

ruct

ure

isbu

ilt o

n a

finite

set

of

disj

oint

G-s

fruc

ture

sF

OG

(her

e, G

( 0-

0)

The

spe

cies

F'

A F

'- st

ruct

ure

on U

isra

F-s

truc

ture

on U

+ f4

ti

TH

EO

RE

M. I

f F a

nd G

are

spe

cies

, the

n(F

+G

)(x)

= F

(x)

+ G

(z),

(F-

= F

0c)

GO

O,

CF

o 6)

(21=

F(G

Oe)

), C

ifF

'Cx)

=F

rac)

.

EX

AM

PLE

S /

AP

PLI

CA

TIO

NS

1) E

= E

.* E

odd

E (

X)

- E

even

CX

) E

oda

OC

)

that

is,

ez=

cos

t,x

sinb

2) L

et D

be

the

spec

ies

of d

eran

gem

ents

,i.e

., pe

rmut

atio

ns w

ithou

t fix

ed p

oint

s, th

enS

E D

mss Afr

ls.

S(x

)=-

EC

x)D

(x)

-riz

a- =

ex

3) C

x.)

Dw

r.:

d =

num

ber

of d

eran

gem

ents

of

n ob

Ject

s

Ot 7

21

31

Page 13: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

A.

1920

3)E

nd =

S °

A

4?lc

"*

4e.

)41

(ol

441

r414

'.0

4.-

:(4*

)4

?/.

C07

./._o

va;

/ --C

ick-

,04-

`.4t

.4,

®17

--0 /

\E

nci(x

)-z.

S(k(

x))

E" n

-rn

s.- 1-

Ak)

n"N

alP

I!

AM

=yi

nz"

Tv

n

LQ

....."

..,...

.

,4

,f)

\,),

k..)

,,om

u.t-

o),.;

*a4,

/.

f4.

-

s(x)

= E

(c(1

))ix

Eva

)41

60=

(m-

)!

4b)

Let

SO

> b

e th

e sp

ecie

s of

per

mut

atio

nsha

ving

* c

ycle

san

dE

kbe

the

spec

ies

of *

-set

s,

then

S s

Eko

44,

Edt

(x)=

S(*`

)(x

)"1

6 E

it(03

e1)

rg,,

A,.

=nu

mbe

r of

per

mut

atio

ns o

f n p

oint

s ha

ving

k c

ycle

s

abso

lute

val

ue o

f Stir

ling

num

ber

of th

e fir

stki

nd

=E

no,,,

..tle

f+

VII

> 0

,41(

rt,1

01

Page 14: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

r

<7,

2122

5a)

33=

--E

0E+

Whe

re E

. is

the

spec

ies

ofno

n-em

pty

sets

.

E+

(x)

=e

i =B

C3e

)= E

(E+

Cx)

)

=ee

e''

ee

It fo

llow

s th

at6=

num

ber

ofpa

rtiti

ons

of a

set

of n

ele

men

ts

I

E.

L.n

Thi

s is

Dob

insk

i's fo

rmul

ae

.fo

r th

e n

th B

ell n

umbe

r4m

0

5b)

Let .

B<le

>be

the

spec

ies

of p

artit

ions

havi

ng *

cla

sses

and

Eli

be th

e sp

ecie

s of

*-s

ets,

<4e

>B

= E

lio(2

3= [

num

ber

of p

artit

ions

of n

poi

nts

into

A c

lass

esS

tirlin

g nu

mbe

r of

the

seco

nd k

ind

Igr

i*I

riin

nr)

'rh

t*

YIL

> 0

6)=

E. E O

N 2

= (

E4

ex

num

ber

of s

ubse

ts o

f a s

et o

f r, e

lem

ents

2"(k

now

n!)

A7)

Let S

be

the

spec

ies

ofpe

rmut

atio

ns^

havi

ng o

nly

even

cyc

les

:S

.--

E0C

even

m.e

c.,..

(2).

. eil.

,Fc

,

V7-

77

z, .

is 3

2. s

t..af

t-it

if h

= 2

k.,

0ot

herw

ise

8)-

efil

140.

414

est

L'(x

)=(L

fr))

t=

xl(k

now

n!)

Page 15: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

2324

9)C

;=L

(aga

inI

)

lid(X

)1=

144

4.00

dx

Lod

d=

LI

even

but

Pb'c

even

12)

A=

X' (

E°A

)

I./

= -

= X

(xl-

E00

0)z e

ik(x

)A

(30

4.14

x)X

ann

11)

B1

E B

recu

rren

ce)

IliB

(2)

1=E

(L)B

0011

, ex-

33(z

)bh

. I(*

)*m

e

13)

Let

be th

e sp

ecie

s of

ver

tebr

ates

( a

vert

ebra

te is

a p

oint

ed r

oote

d tr

ee )

= L

OA

,.,i,

.,0f

/...

......

...._

__\.a

. a c

e....

.,....

:fr

(ze

esi

," 0

1_,A

/_.:

e--.

. .4

\se

s-..

4....

..-w

,...

..., /

4,

.-._

....

as(5

-o-*

il,-,

.....

...

I. v

e(x)

.. L

(A

(20)

5 -

1_A

(.)

5E

A44

4Cx)

A/4

..r.

n a

. r.

num

ber

of e

nclo

func

tions

on

P e

lem

ents

n"a.

r. n

" -I

(Joy

al)

Page 16: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

7:V

2526

14)

gl=

the

spec

ies

of fo

rest

s of

roo

ted

tree

s

a'=

41'

..

1/4.

fe-7

,1.

4k.

Hen

ce, t

he n

umbe

r of

bal

lot o

utco

mes

for

nca

ndid

ates

Is

*"

16)

Let 8

4 be

the

spec

ies

of b

allo

ts.

43.0

1 =

L0

Ell.

&LI

N L

tE.6

0 =

L (

ex-

i)as

430

(7);

'4-

----

--T

er5u

-kt5

+6.

1)11

760

claw

nil

titQ

,nu

mbe

r of

fore

sts

of r

oote

d tr

ees

onn

poin

ts,o

v-I

=+

I j

15)

Aul

t=

Et

21,1

4(z)

,..e

it'`,

''`)

Zia

(29

=L

t A. (

x.)

= L

te,)

,T.;

inintegerY)

17)

Inv

= E

a+

E,,)

"1.1

1

oi0*

* ef

f

IL.

"0

Ilith

eiV

oirn

ifbite

e:vv

r+0:

34x1

n:ol

eutl%

en4:

onn

elem

ents

Is

al)1

.3.5

-42*

-0

18)

Cla

ssic

al fo

rmul

as o

f Cal

culu

s ho

ld

For

exam

ple

: (F-

0 6,

Y=

(Fio

&)G

' [ch

ain

rule

]

G V

G -

Rgb

rG

)(v-

"N

.,

11cs

;LN

.,0

-*(r

*aF.

6G

.R::

oJC

's

Page 17: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

2728

PO

SS

IBLE

TE

AC

HIN

G /

LEA

RN

ING

AC

TIV

ITIE

S(

from

ele

men

tary

to a

dvan

ced

)

To

find,

bui

ld o

r dr

aw c

ombi

nato

rial

stru

ctur

es fr

om r

eal-l

ife s

ituat

ions

or fr

om c

oncr

ete

/ abs

trac

ts o

bjec

ts.

To

deci

de w

heth

er tw

o st

ruct

ures

of a

giv

en s

peci

es a

re e

qual

or

not.

To

mak

e a

com

plet

e an

d no

n-re

petit

ive

list o

f str

uctu

res

belo

ngin

g to

a g

iven

spec

ies,

labe

lled

by a

giv

en (

smal

l) se

t.

To

mak

e a

com

plet

e an

d no

n-re

petit

ive

list o

f unl

abel

led

stru

ctur

es b

elon

ging

to a

giv

en s

peci

es o

n n

indi

stin

guis

habl

eel

emen

ts (

n sm

all).

To

find

com

bina

toria

l equ

atio

ns a

ssoc

iate

dto

spe

cies

(an

d vi

ce-v

ersa

).

To

find

enum

erat

ive

or s

truc

tura

l pro

pert

ies

of s

peci

es fr

om th

eir

com

bina

toria

l equ

atio

ns(v

ia s

erie

s ex

pans

ions

, for

exa

mpl

e).

To

find,

bui

ld o

r dr

aw c

ombi

nato

rial

stru

ctur

es fr

om r

eal-l

ife s

ituat

ions

or fr

om c

oncr

ete

/ abs

trac

t obj

ects

.

Riv

ers

mak

ing

a (p

lane

) tr

ee

Flo

wer

s

1014

Vis

:47

Sitt

ing

arou

nd a

rou

nd ta

ble

Page 18: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

2930

To

deci

de w

heth

er tw

o st

ruct

ures

of a

giv

en s

peci

es a

re e

qual

or

not.

s-b-c-d-e

f-g-h-I-J

a-g-h-l-J

I1

1i

f-g-h-i-J = a-b-e-d-o * f-b-c-d-e,

To

mak

e a

com

plet

e an

d no

n-re

petit

ive

list o

f str

uctu

res

belo

ngin

g to

a g

iven

spec

ies,

labe

lled

by a

giv

en (

smal

l) se

t.

The

16

tree

s la

belle

d by

{ a

, b, c

, d }

:a-

b-c-

da-

c-b-

da-

b-d-

ca-

d-b-

ca-

c-d-

ba-

d-c-

b

b-a-

d-c

b-d-

a-c

b-a-

c-d

0-c-

a-d

c-a-

b-d

c-b-

a-d

b\a/

dI G

b\c/

a

I d

cd

b I ab\d/ a

I G

To

mak

e a

com

plet

e an

d no

n-re

petit

ive

list o

f unl

abel

led

stru

ctur

es b

elon

ging

to a

giv

en s

peci

es o

n n

indi

stin

guis

habl

eel

emen

ts (

n sm

all),

The

2 u

nlab

elle

d tr

ees

on 4

iden

tical

ele

men

ts:

(0-4

,-0-

411

Y

To

find

com

bina

toria

l equ

atio

ns a

ssoc

iate

dto

spe

cies

(an

d vi

ce-v

ersa

).

To

find

enum

erat

ive

or s

truc

tura

l pro

pert

ies

of s

peci

es fr

om th

eir

com

bina

toria

l equ

atio

ns(v

ia s

erie

s ex

pans

ion,

for

exam

ple)

.

Page 19: Reproductions supplied by EDRS are the best that can be ...combinatorial structures in the context of modern combinatorics can easily lead to interesting teaching and learning activities

<St-- OW, 7q

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REPRODUCTION RELEASE(Specific Document)

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PROCCEDI N CI- S acx, 0 A-10,ML)A-c._ i3 6--Author(s): GA t K6-- 5 r AA AA. r- 6 'DAV )Corporate Source: 11-tech,,A,ry,,,ZZ,0

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