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A063437 Cardinality of largest critical set in any Latin square of order n. 1
0, 1, 3, 7, 11, 18 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

A critical set in an n X n array is a set C of given entries such that there exists a unique extension of C to an n X n Latin square and no proper subset of C has this property.

a(9) >= 45. - Richard Bean (rwb(AT)eskimo.com), May 01 2002

For n sufficiently large (>= 295), a(n) >= (n^2)*(1-(2 + log 2)/log n) + n*(1 + (log(8*Pi)/log n) - (log 2}/(log n). Bean and Mahmoodian also show a(n) <= n^2 - 3n + 3. - Jonathan Vos Post, Jan 03 2007

REFERENCES

Richard Bean and E. S. Mahmoodian, A new bound on the size of the largest critical set in a Latin square, Discrete Math., 267 (2003), 13-21.

R. Bean and Ebadollah S. Mahmoodian, A new bound on the size of the largest critical set in Latin squares, Discrete Math, to appear.

LINKS

Table of n, a(n) for n=1..6.

Richard Bean and E. S. Mahmoodian, A new bound on the size of the largest critical set in a Latin square

Mahya Ghandehari, Hamed Hatami and Ebadollah S. Mahmoodian, On the size of the minimum critical set of a Latin square, Journal of Discrete Mathematics. 293(1-3) (2005) pp. 121-127

Hamed Hatami and Ebadollah S. Mahmoodian, A lower bound for the size of the largest critical sets in Latin squares, Bulletin of the Institute of Combinatorics and its Applications (Canada). 38 (2003) pp. 19-22

CROSSREFS

Sequence in context: A072456 A138659 A020590 * A190711 A210977 A049792

Adjacent sequences:  A063434 A063435 A063436 * A063438 A063439 A063440

KEYWORD

nonn

AUTHOR

Ahmed Fares (ahmedfares(AT)my-deja.com), Jul 24 2001

EXTENSIONS

The next terms satisfy a(7) >= 25, a(8) >= 37, a(9) >= 44, a(10) >= 57. In the reference it is proved that, for all n, a(n) <= n^2 - 3n + 3.

STATUS

approved

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Last modified December 8 19:05 EST 2016. Contains 278948 sequences.