Abstract
We study the threshold probability for the existence of a panchromatic coloring with r colors for a random k-homogeneous hypergraph in the binomial model H(n, k, p), that is, a coloring such that each edge of the hypergraph contains the vertices of all r colors. It is shown that this threshold probability for fixed r < k and increasing n corresponds to the sparse case, i. e. the case
Originally published in Diskretnaya Matematika (2019) 31, №2, 84–113 (in Russian).
Funding statement: The study was performed under the RFBR grant No. 16-11-10014.
References
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4.64.6 Appendix
In the Appendix we prove the auxiliary technical statements.
Assertion 2
There existsk0 < ∞such that for allk > k0 and
Proof
Note that this inequality is valid for all r ⩽ 11 and sufficiently large k. For r > 11 we have r2 − (4/3)r + 2/3 < r2 − (5/4)r and
If r > 11, then
for all sufficiently large k.
Assertion 3
There existsk0 < ∞such that for allk > k0 and
Proof
In the first inequality the factors of the left hand side of
follows from the monotone descreasing of (r − 2)/(r2 − r) with respect to r.
It is sufficient to show that for large k the value
Assertion 4
There existsk0 < ∞ such that for all k > k0 and
Proof
It is sufficient to show that
follows from the fact that the function
Assertion 5
There existsk0 < ∞ such that for allk > k0,
Proof
Note that
So, the estimated value does not exceed
this expression for all sufficiently large k implies the desired upper bound
Assertion 6
There existsk0 < ∞ such that for allk > k0,
Proof
From the conditions on the parameters we deduce that
Further,
where the last inequality also is satisfied for all sufficiently large k.
Assertion 7
There existsk0 < ∞ such that for allk > k0,
Proof
It is sufficient to show that each of the first three negative summands is 4 times smaller than the last summand. Let us compare each of them with the last summand. Begin with the first one:
for all sufficiently large k. Now consider the second summand:
It remains to consider the third summand:
for all sufficiently large k.
Assertion 8
There existsk0 < ∞ such that for allk > k0,
Proof
Note that
In view of condition on the relation between r and k the maximal summand in the second parenthesis is the first one. Hence, the left hand side of our inequality does not exceed
The assertion 8 is proved.
© 2021 Walter de Gruyter GmbH, Berlin/Boston
Articles in the same Issue
- Frontmatter
- Reduction of the integer factorization complexity upper bound to the complexity of the Diffie–Hellman problem
- Pseudo orthogonal Latin squares
- Panchromatic colorings of random hypergraphs
- On the connectivity of configuration graphs
- Asymptotics with remainder term for moments of the total cycle number of random A-permutation
- On the dependence of the complexity and depth of reversible circuits consisting of NOT, CNOT, and 2-CNOT gates on the number of additional inputs
- Letter to the Editor
Articles in the same Issue
- Frontmatter
- Reduction of the integer factorization complexity upper bound to the complexity of the Diffie–Hellman problem
- Pseudo orthogonal Latin squares
- Panchromatic colorings of random hypergraphs
- On the connectivity of configuration graphs
- Asymptotics with remainder term for moments of the total cycle number of random A-permutation
- On the dependence of the complexity and depth of reversible circuits consisting of NOT, CNOT, and 2-CNOT gates on the number of additional inputs
- Letter to the Editor