Concentration Inequalities and Expected Suprema
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A cheatsheet of some measure concentration results. Taken from:
- Philippe Rigollet’s High-Dimensional Statistics class notes.
- Gabor Lugosi’s Concentration of Measure Inequalities class notes.
- Vladimir Koltchinskii Oracle Inequalities in Empirical Risk Minimization and Sparse Recovery Problems, letcture notes.
- Larry Wasserman’s Concentration of Measure class notes.
- Shalev-Shwartz, Shai, and Shai Ben-David. Understanding Machine Learning: From Theory to Algorithms. New York, NY: Cambridge University Press, 2014.
Preliminaries
Classes of Distributions
SubGaussian SubExponential
Complexity Measures in Function Spaces
Linear Dimension
VC dimension
Uniform Covering Numbers
Random Covering Numbers
Shattering Numbers
Bracketing Numbers
Bracketing Entropy
Generic Chaining Complexities
Conecntration Inequalities
Of a Single Random Variable
Of Sums of Random Variables
Of Suprema of Stochastic Processes
Markov’s Inequality
Polynomial decay ($t^{-1}$) of tail probability w.r.t. the expectation.
Chebyshev’s inequality
Polynomial decay $t^{-2}$ of tail probability w.r.t. the variance.
Generalized Chernoff bound
subExponenitial decay of tail probability of sums.
Sums of subGaussian are subGaussian
Gaussian Tail Inequality
Bounds the tail of a Gaussian w.r.t. its density (thus, a subGaussian inequality).
Square of subGaussian
The square of a subGaussian (e.g. Chisq) is subExponential with related scale parameter.
Hoffeding
subGaussian decay of tail probability of sums of bounded support random variables (garanteeing subGaussian tails).
McDiarmid’s Inequality
A bounded difference function is subGaussian concentrated.
Shawe-Taylor and Cristianini
Bound on the sum of a bounded function of some random variables.
Bennet’s Inequality
Tighter than subGaussian decay of tails of sums.
Sum of subExp is subExp
Bernstein’s Inequality
subExp or subGausian tails for sums of subExponenital variables.
Talagrand’s Inequality
A uniform version of Bernstein’s Inequality.
Gine and Guillou Inequality
Efron-Stein Inqeuality
A.k.a. Influence Inequality, MG Bound on Variance Bound on the variance of an arbitrary function of random variables, w.r.t. the sum of the coordinate independent contributions. Very powerful when compounding with Che
Slud’s Inequality
A subGaussian deconcentration inequality for the Binomial distribution. Put differently, the Binomial converges to a Gaussian, but has heavier tails all along the way.
Maximal Inequality
- Over finite set
- Over convex polytope
- Over l_2 ball.
Moment Bounds
The following bound the expectation, and not the tail probabilities.
Non Negative subGaussian
The expectation of a non-negative subGaussian decays like $n^{-1/2}$.
Expected Maximum over a Finite Set
The expectation of the max of subGaussians decays like $\sqrt{\log n}$.
Expected Maximum with Covering Number
The expectation of the max of subGaussians decays like the integrated log of the covering number.