Stable
Matchings

The story, all names, characters, and incidents portrayed in this class are fictitious.

No identification with actual persons is intended or should be inferred.

Blocking Pairs

When A is matched to B

and X is matched to Y

but A prefers Y over B

and Y prefers A over X.

Goal: Stable Marriage

An assignment with

no blocking pairs.

Men = [n] & Women = [n]

ManPref[m, j] is the identity of the j-th ranked woman in m’s preference list 

WomanPref[w, j] is the identity of the jth
ranked man in w’s preference list.

Next[w] →  the rank of the best unproposed man for w.

Current[m] →   is the identity of the woman m is currently
engaged to and is −1 otherwise

FreeWomenList is the set of unmatched women.

Rank is an n ×n 2D array such that Rank[m,w] is the rank of w in m’s preference list.

Consider the following instance of the stable matching problem for 4 men (PQRS) and 4 women (WXYZ).

& P: W>X>Y>Z
& Q: X>Y>Z>W
& R: W>X>Z>Y
& S: X>Y>W>Z

and


W: S>Q>R>P
X: P>S>Q>R
Y: R>P>Q>S
Z: R>P>S>Q

Does the algorithm terminate?

Does the algorithm produce a valid matching?

Does the algorithm produce a stable matching?

How long does the algorithm need to run?

Copy of Stable Matchings

By Neeldhara Misra

Copy of Stable Matchings

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