All reports by Author Nikhil Mande:

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TR19-082
| 2nd June 2019
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Andrej Bogdanov, Nikhil Mande, Justin Thaler, Christopher Williamson#### Approximate degree, secret sharing, and concentration phenomena

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TR19-027
| 1st March 2019
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Mark Bun, Nikhil Mande, Justin Thaler#### Sign-Rank Can Increase Under Intersection

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TR19-007
| 17th January 2019
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Arkadev Chattopadhyay, Meena Mahajan, Nikhil Mande, Nitin Saurabh#### Lower Bounds for Linear Decision Lists

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TR18-176
| 26th October 2018
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Arkadev Chattopadhyay, Nikhil Mande, Suhail Sherif#### The Log-Approximate-Rank Conjecture is False

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TR17-083
| 5th May 2017
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Arkadev Chattopadhyay, Nikhil Mande#### Weights at the Bottom Matter When the Top is Heavy

Revisions: 1

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TR17-062
| 9th April 2017
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Arkadev Chattopadhyay, Nikhil Mande#### Dual polynomials and communication complexity of XOR functions

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TR16-095
| 7th June 2016
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Arkadev Chattopadhyay, Nikhil Mande#### Small Error Versus Unbounded Error Protocols in the NOF Model

Revisions: 1
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Comments: 1

Andrej Bogdanov, Nikhil Mande, Justin Thaler, Christopher Williamson

The $\epsilon$-approximate degree $\widetilde{\text{deg}}_\epsilon(f)$ of a Boolean function $f$ is the least degree of a real-valued polynomial that approximates $f$ pointwise to error $\epsilon$. The approximate degree of $f$ is at least $k$ iff there exists a pair of probability distributions, also known as a dual polynomial, that are perfectly ... more >>>

Mark Bun, Nikhil Mande, Justin Thaler

The communication class $UPP^{cc}$ is a communication analog of the Turing Machine complexity class $PP$. It is characterized by a matrix-analytic complexity measure called sign-rank (also called dimension complexity), and is essentially the most powerful communication class against which we know how to prove lower bounds.

For a communication problem ... more >>>

Arkadev Chattopadhyay, Meena Mahajan, Nikhil Mande, Nitin Saurabh

We demonstrate a lower bound technique for linear decision lists, which are decision lists where the queries are arbitrary linear threshold functions.

We use this technique to prove an explicit lower bound by showing that any linear decision list computing the function $MAJ \circ XOR$ requires size $2^{0.18 n}$. This ...
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Arkadev Chattopadhyay, Nikhil Mande, Suhail Sherif

We construct a simple and total XOR function $F$ on $2n$ variables that has only $O(\sqrt{n})$ spectral norm, $O(n^2)$ approximate rank and $n^{O(\log n)}$ approximate nonnegative rank. We show it has polynomially large randomized bounded-error communication complexity of $\Omega(\sqrt{n})$. This yields the first exponential gap between the logarithm of the ... more >>>

Arkadev Chattopadhyay, Nikhil Mande

Proving super-polynomial lower bounds against depth-2 threshold circuits of the form THR of THR is a well-known open problem that represents a frontier of our understanding in boolean circuit complexity. By contrast, exponential lower bounds on the size of THR of MAJ circuits were shown by Razborov and Sherstov (SIAM ... more >>>

Arkadev Chattopadhyay, Nikhil Mande

We show a new duality between the polynomial margin complexity of $f$ and the discrepancy of the function $f \circ$ XOR, called an XOR function. Using this duality,

we develop polynomial based techniques for understanding the bounded error (BPP) and the weakly-unbounded error (PP) communication complexities of XOR functions. ...
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Arkadev Chattopadhyay, Nikhil Mande

We show that a simple function has small unbounded error communication complexity in the $k$-party number-on-forehead (NOF) model but every probabilistic protocol that solves it with sub-exponential advantage over random guessing has cost essentially $\Omega\left(\frac{\sqrt{n}}{4^k}\right)$ bits. Such a separation was first shown for $k=2$ independently by Buhrman et al. ['07] ... more >>>