Structure Of Boolean Almost Low Degree Functions On The Biased Cube

Published on ● Video Link: https://www.youtube.com/watch?v=4Rd11uLCVro



Duration: 57:20
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Yuval Filmus (Technion - Israel Institute of Technology)
https://simons.berkeley.edu/talks/yuval-filmus-technion-israel-institute-technology-2023-07-28
Structural Results

The FKN theorem states that if a Boolean function on the Boolean cube is close to degree 1, then it is close to a dictator.
Similarly, the Kindlerโ€“Safra theorem states that if a Boolean function on the Boolean cube is close to degree d, then it is close to a junta.

The picture becomes more interesting when we study functions on the p-biased Boolean cube.
If a Boolean function is ๐œ€-close to degree 1, then (up to negation) it is O(๐œ€)-close to a maximum of O(โˆš๐œ€/p+1) coordinates, and so O(โˆš๐œ€+p)-close to a constant function.
A similar statement holds for functions close to degree d, but the corresponding structure is more complicated.

Another setting we might discuss is functions on the symmetric group.
If a Boolean function is ๐œ€-close to degree 1, then it is O(โˆš๐œ€)-close to a dictator (suitably defined), and O(๐œ€)-close (up to negation) to a union of โ€œmostly disjointโ€ cosets.
A similar statement should hold for degree d, where the function ought to be close to a (suitably defined) decision tree of depth poly(d).

Joint work with Irit Dinur (Weizmann Institute) and Prahladh Harsha (TIFR).







Tags:
Simons Institute
theoretical computer science
UC Berkeley
Computer Science
Theory of Computation
Theory of Computing
Structural Results
Yuval Filmus