Resource Allocation Polytope Games: Uniqueness of ...

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Telecom SudParis, Universite Paris-Saclay, CNRS, France. INRIA Sophia Antipolis-Mediterranee, France. Resource Allocation Polytope Games. A. B w. B1 w.
Resource Allocation Polytope Games Uniquess of Equilibrium, PoS, PoA Swapnil Dhamal, Walid Ben-Ameur, Tijani Chahed, and Eitan Altman Telecom SudParis, Universite Paris-Saclay, CNRS, France INRIA Sophia Antipolis-Mediterranee, France

Resource Allocation Polytope Games

A x1 wA1

x2

x3

w wA2 A2

w wA3

wB2

wB3

w B1

y2

y1

y3

Price of Stability and Price of Anarchy

Uniqueness of PSNE

xn wAn A4

Unique PSNE if and only if IOS is nonconflicting and either (a) common contiguous set consists of at most one node, or (b) all nodes in common contiguous set invested on by only one player in the IOS.

1

3

2

4

2

3

1

(wBiyi + αwAixi)

subject to

xi, yi ≥ 0, ∀i ∈ N X X xi ≤ kA, yi ≤ kB

   

i∈N

πA( jA )

JA

IB

πB( jB )

JB

CA = {1, 2} (x, y) is a PSNE if and only if ∃ jA, jB s.t.

1

3

2

4

CB = {4, 2}

∀i ∈ IA ∪ IB : xi + yi = 1

i∈N

    

IA

3

i∈N

uB (x, y) =

No universal constant bound for PoA

CB = {4}

(wAixi + βwBiyi),

X

α, β > −1 =⇒ PoS = 1

CAB = {} 4

uA(x, y) =

i∈N

CA = {1, 2}

B

X

For i = πA(jA), πB (jB ) : xi + yi ≤ 1

CAB = {2} 4

3

2

∀i ∈ JA : xi = 0, yi ≤ 1

1

3 CA = {1, 2, 3}

∀i ∈ JB : yi = 0, xi ≤ 1 X X xi = kA, yi = kB , ∀i ∈ N : xi, yi ≥ 0

CB = {2, 3}

Worst PSNE:

i∈N

xi + yi ≤ 1, ∀i ∈ N 1

3

2

4

Polytope game - Linear common coupled constraints - Bilinear utility functions

CAB = {2, 3} 2

4

3

1

3

i∈N

i∈N

For jA ← dkAe to dkA + kB e For jB ← dkB e to dkA + kB e X  min xi zAi − max{zBi − zBπB (jB ), 0} x

i∈N

Exact Restricted Potential Game

subject to

CA = {1, 2, 3} ∀x0, x00 ∈ F (y) : uA(x0, y) − uA(x00, y) X X = (wAix0i + wBiyi) − (wAix00i + wBiyi) i∈N 0

00

00

∀y , y ∈ F (x) : uB (x, y ) − uB (x, y ) X X 0 00 = (wAixi + wBiyi) − (wAixi + wBiyi ) i∈N

1

3

2

∀i ∈ N : xi ∈ [0, 1]

4

CB = {2, 3, 1}

∀i ∈ IA ∩ JB : xi = 1 X xi + xπA(jA) = kA

CAB = {1, 2, 3}

i∈N 0

(zAixi + zBiyi)

Characterization of PSNE

wB4 Bn

yn

uA(x, y) + uB (x, y) =

X

2

1

3

4

7

i∈IA

(X πB (jB ) ∈ IA :

xi + xπB (jB ) = jB − kB

i∈IB Socially Optimal Strategy Profile

i∈N

Exact restricted potential game P Potential fn Φ(x, y) = i∈N (wAixi +wBiyi)

zAi = (1 + α)wAi, zBi = (1 + β)wBi

X  xi ≥ (jB − 1) − kB    i∈IB πB (jB ) ∈ / IA : X   xi + xπB (jB ) ≤ jB − kB   i∈IB

Non-conflicting Independent Optimal Strategies

IOS of a player is its strategy in absence of other player. IOS (ˆ x, y ˆ) is non-conflicting if and only if xˆi + yˆi ≤ 1, ∀i ∈ N . Conflicting IOS =⇒ Non-unique PSNE Non-conflicting IOS =⇒ 6 Unique PSNE

AAAI 2018

max max x

y≤1−x

X i∈N

= max max x

jB

(zAixi + zBiyi) Paradox

X

zAixi +

i∈N

X

(1 − xi)zBi

i∈IB



+ kB −

X



(1 − xi) zBπB (jB )

i∈IB

h

 = max max xi zAi − max{zBi − zBπB (jB ), 0} x jB i∈N i X + max{zBi − zBπB (jB ), 0} + kB zBπB (jB ) i∈N

X

M

w mA2

w mB1

w MB2

1

2

M >> m α=β=0 kA = kB = 1 M +M PoA = m+m

M + M − M If kB = 1 − , PoA = =1 M + M − M