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Pseudorandom generators for polynomials
Encyclopedia
In theoretical computer science
a pseudorandom generator for low-degree polynomials is an efficiently computable function whose output is indistinguishable from the uniform distribution by evaluation of low-degree polynomials in the following sense.
for polynomials of degree
over a Finite field
F is an efficient procedure that stretches
field elements into
field elements and fools any
polynomial of degree d in n variables over F: For every such polynomial p, the statistical distance between the distributions
, for uniform
in
, and
, for uniform
in
, is at most a small
.
which give constructions with seed length
(this is optimal up to constant factors). Following the sequence of papers (http://www.ccs.neu.edu/home/viola/papers/gen.pdf, http://shachar.lovett.googlepages.com/prg_poly.pdf) it was established in http://www.ccs.neu.edu/home/viola/papers/d.pdf that a sum of
small-bias spaces fools degree
polynomials. This gives a construction with seed length
.
Theoretical computer science
Theoretical computer science is a division or subset of general computer science and mathematics which focuses on more abstract or mathematical aspects of computing....
a pseudorandom generator for low-degree polynomials is an efficiently computable function whose output is indistinguishable from the uniform distribution by evaluation of low-degree polynomials in the following sense.
Definition
A pseudorandom generator![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-1.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-2.gif)
Finite field
In abstract algebra, a finite field or Galois field is a field that contains a finite number of elements. Finite fields are important in number theory, algebraic geometry, Galois theory, cryptography, and coding theory...
F is an efficient procedure that stretches
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-3.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-4.gif)
polynomial of degree d in n variables over F: For every such polynomial p, the statistical distance between the distributions
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-5.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-6.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-7.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-8.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-9.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-10.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-11.gif)
Construction
The case of linear polynomials is solved by small-bias spacesEpsilon-Biased Sample Spaces
In computer science \epsilon-biased sample spaces, also known as \epsilon-biased generators or small-bias probability spaces, refer to small probability spaces that approximate larger spaces as defined below...
which give constructions with seed length
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-12.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-13.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-14.gif)
![](http://image.absoluteastronomy.com/images/formulas/5/1/4513855-15.gif)