Concepts37

📚TheoryIntermediate

Concentration Inequalities

Concentration inequalities give high-probability bounds that random outcomes stay close to their expectations, even without knowing the full distribution.

#concentration inequalities#hoeffding inequality#chernoff bound+12
📚TheoryIntermediate

Markov Chain Theory

A Markov chain is a random process where the next state depends only on the current state, not the full history.

#markov chain#transition matrix#stationary distribution+12
📚TheoryIntermediate

Spectral Graph Theory

Spectral graph theory studies graphs by looking at eigenvalues and eigenvectors of matrices like the adjacency matrix A and Laplacians L and L_norm.

#spectral graph theory#laplacian#normalized laplacian+12
📚TheoryIntermediate

Parallel Algorithm Theory

Parallel algorithm theory studies how to solve problems faster by coordinating many processors that share work and memory.

#pram#work-span#parallel prefix sum+12
📚TheoryIntermediate

Online Algorithm Theory

Online algorithms make decisions step by step without seeing the future and are judged against an all-knowing offline optimum.

#online algorithms#competitive analysis#ski rental+12
📚TheoryIntermediate

Approximation Algorithm Theory

Approximation algorithms deliver provably near-optimal solutions for NP-hard optimization problems within guaranteed factors.

#approximation algorithms#ptas#fptas+12
📚TheoryIntermediate

Randomized Algorithm Theory

Randomized algorithms use random bits to make choices that simplify design, avoid worst cases, and often speed up computation.

#randomized algorithms#las vegas#monte carlo+12
📚TheoryIntermediate

Amortized Analysis

Amortized analysis measures the average cost per operation over a worst-case sequence, not over random inputs.

#amortized analysis#aggregate method#accounting method+12
📚TheoryIntermediate

Computability Theory

Computability theory studies the boundary between what can and cannot be computed by any algorithm.

#computability theory#turing machine#church-turing thesis+12
📚TheoryIntermediate

Halting Problem

The Halting Problem asks whether a given program P will eventually stop when run on input x; there is no algorithm that correctly answers this for all P and x.

#halting problem#undecidable#diagonalization+12
📚TheoryIntermediate

NP-Completeness

NP-completeness classifies decision problems that are both in NP and as hard as any problem in NP via polynomial-time reductions.

#np-complete#np-hard#polynomial-time reduction+12
📚TheoryIntermediate

ELBO (Evidence Lower Bound)

The Evidence Lower Bound (ELBO) is a tractable lower bound on the log evidence log p(x) that enables learning and inference in latent variable models like VAEs.

#elbo#variational inference#vae+12