#P
#P (sharp P) is a complexity class introduced by Leslie Valiant in 1979 for functions counting the accepting paths of a nondeterministic polynomial-time machine, equivalently the number of solutions of NP problems.
#P (complexity class)
#P ("sharp P") is a complexity class of counting problems, introduced by Leslie Valiant in 1979; where NP asks whether a solution exists, #P asks how many.
#P-complete
#P-complete problems are the hardest counting problems in complexity class #P, defined by Leslie Valiant in 1979; canonical examples are #SAT, counting satisfying assignments, and the matrix permanent.
⊕P
⊕P, also written parity-P, is a complexity class of decision problems where a nondeterministic polynomial-time machine accepts when it has an odd number of accepting paths.
2014 celebrity nude photo leak
The 2014 celebrity nude photo leak, also known as Celebgate, was the theft and online publication of nude photos of more than 100 celebrities.
2017 Equifax data breach
The 2017 Equifax data breach was a cyberattack on credit bureau Equifax that exposed the personal data of roughly 147 million people through an unpatched Apache Struts vulnerability.
2023 AI Safety Summit
The 2023 AI Safety Summit was an international conference on AI safety held at Bletchley Park, UK, on 1–2 November 2023, producing the 28-country Bletchley Declaration.
2B (Nier: Automata)
2B, formally YoRHa No. 2 Type B, is a fictional battle android and protagonist of the 2017 action role-playing game NieR: Automata by PlatinumGames and Square Enix.
3D computer graphics
3D computer graphics, also called three-dimensional computer graphics, are graphics in which scenes are described mathematically in 3D and rendered into 2D images, using models, materials, and algorithms like rasterization and ray tracing.
3D convolutional neural network
A 3D convolutional neural network (3D CNN) applies convolutional filters across multiple axes of a data volume, learning features from video and volumetric images such as CT or MRI scans.
3D image reconstruction
3D image reconstruction is the set of computational methods that recover a 3D volume or surface from 2D images or projections, underpinning CT, MRI, PET, ultrasound, and electron microscopy.
3D morphable model
A 3D morphable model (3DMM) is a statistical generative model of 3D face shape and texture, introduced by Volker Blanz and Thomas Vetter at SIGGRAPH 1999.
3D parallelism
3D parallelism is a distributed deep-learning training strategy combining tensor, pipeline, and data parallelism, popularized by DeepSpeed and Megatron-LM and used to train models with over a trillion parameters.
3D reconstruction
3D reconstruction is the set of computational methods that build a 3D model of an object or scene from images, depth data, or point clouds.
3D Shape Context
The 3D Shape Context (3DSC) is a shape descriptor for 3D point data that represents surface shape around a point as a histogram, used for object recognition and registration.
3D surface reconstruction
3D surface reconstruction is a computational geometry method that converts unorganized 3D point clouds, typically from scanners, into continuous surface models such as triangle meshes or implicit fields.
3N-MCTS
3N-MCTS is a synthesis planning algorithm that combines Monte Carlo tree search with three deep neural networks to find retrosynthetic routes, introduced in a 2018 Nature paper.
6D object pose estimation
6D object pose estimation is the computer vision task of estimating a rigid object's 3D position and orientation from camera images, needed for robotic grasping, augmented reality, and autonomous driving.
7-Scenes
7-Scenes is a Microsoft Research dataset of tracked RGB-D camera frames from seven indoor scenes, published in June 2013 as a standard benchmark for camera relocalization and tracking.
A Logical Calculus of the Ideas Immanent in Nervous Activity
A 1943 paper by Warren McCulloch and Walter Pitts modeling the neuron as a binary threshold device, widely seen as the first serious attempt to model computation in the brain.
A Relational Model of Data for Large Shared Data Banks
Codd's 1970 CACM paper (A Relational Model of Data for Large Shared Data Banks) that founded the relational database model: n-ary relations, normalization, data independence, and the universal data sublanguage behind SQL.
A-Lab (Berkeley Lab)
The A-Lab is an autonomous laboratory at Lawrence Berkeley National Laboratory, begun in 2020, that uses robotics, machine learning, and materials databases to synthesize inorganic powder materials.
A.I. Artificial Intelligence
A.I. Artificial Intelligence is a 2001 American science fiction drama directed by Steven Spielberg, starring Haley Joel Osment as a robot boy programmed to love.
A.X.L.
A.X.L. (2018) is Oliver Daly's sci-fi adventure film, adapted from his Kickstarter-funded short Miles, about teen motocross racer Miles Hill and a robotic military dog code-named Attack, Exploration, Logistics, starring Alex Neustaedter and Becky G.
A* search algorithm
The A search algorithm is a graph search method that finds minimum-cost paths, published in 1968 by Hart, Nilsson, and Raphael at the Stanford Research Institute.
Aadhaar (आधार)
Aadhaar (आधार) is a 12-digit unique identity number issued by India's UIDAI to residents, linking demographics with fingerprints and iris scans; over 1.4 billion numbers exist.
Aardvark Weather
Aardvark Weather is an end-to-end data-driven weather prediction system that turns raw observations into global and local forecasts without conventional numerical weather prediction, described in Nature by University of Cambridge researchers in 2025.
Ab initio structure prediction
Ab initio (de novo) structure prediction is a computational method that builds a 3D protein model from its amino acid sequence alone, without a template structure.
ABBA Voyage
ABBA Voyage is a virtual concert residency in London where digital avatars of the Swedish pop group ABBA perform nightly at the purpose-built ABBA Arena since May 2022.
Abnormal event detection
Abnormal event detection is a computer vision task that localizes unusual activities in video, such as accidents, fights, thefts, and arson, by scoring each frame.