Weizmann Logo
ECCC
Electronic Colloquium on Computational Complexity

Under the auspices of the Computational Complexity Foundation (CCF)

Login | Register | Classic Style



REPORTS > DETAIL:

Revision(s):

Revision #1 to TR16-102 | 4th June 2018 20:03

Bounded Independence versus Symmetric Tests

RSS-Feed




Revision #1
Authors: Ravi Boppana, Johan Hastad, Chin Ho Lee, Emanuele Viola
Accepted on: 4th June 2018 20:03
Downloads: 67
Keywords: 


Abstract:

For a test $T \subseteq \{0,1\}^n$ define $k^*$ to be the maximum $k$ such
that there exists a $k$-wise uniform distribution over $\{0,1\}^n$ whose
support is a subset of $T$.

For $T = \{x \in \{0,1\}^n : \abs{\sum_i x_i - n/2} \le t\}$ we prove $k^* =
\Theta(t^2/n + 1)$.

For $T = \{x \in \{0,1\}^n : \sum_i x_i \equiv c \pmod m\}$ we prove that $k^* =
\Theta(n/m^2 + 1)$. For some $k = O(n/m)$ we also show that any $k$-wise
uniform distribution puts probability mass at most $1/m + 1/100$ over $T$.
Finally, for any fixed odd $m$ we show that there is an integer $k =
(1-\Omega(1))n$ such that any $k$-wise uniform distribution lands in
$T$ with probability exponentially close to $|T|/2^n$; and this
result is false for any even $m$.



Changes to previous version:

Tight bounds, extension to thresholds, and discussion.


Paper:

TR16-102 | 4th July 2016 12:55

Bounded independence vs. moduli





TR16-102
Authors: Ravi Boppana, Johan HÃ¥stad, Chin Ho Lee, Emanuele Viola
Publication: 4th July 2016 12:55
Downloads: 672
Keywords: 


Abstract:

Let $k=k(n)$ be the largest integer such that there
exists a $k$-wise uniform distribution over $\zo^n$ that
is supported on the set $S_m := \{x \in \zo^n : \sum_i
x_i \equiv 0 \bmod m\}$, where $m$ is any integer. We
show that $\Omega(n/m^2 \log m) \le k \le 2n/m + 2$. For
$k = O(n/m)$ we also show that any $k$-wise uniform
distribution puts probability mass at most $1/m + 1/100$
over $S_m$. Finally, for any fixed odd $m$ we show that
there is $k = (1-\Omega(1))n$ such that any $k$-wise
uniform distribution lands in $S_m$ with probability
exponentially close to $|S_m|/2^n$; and this result is
false for any even $m$.



ISSN 1433-8092 | Imprint