A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

P versus NP and other resource-bounded computation.
Questions regarding well-defined instructions for completing a task, and relevant analysis in terms of time/memory/etc.
Reference-request is used when the author needs to know about work related to the question.
Graph theory is the study of graphs, mathematical structures used to model pairwise relations between objects.
Algorithms on graphs, excluding heuristics.
Questions related to NP-hardness and NP-completeness.
Questions related to combinatorics and discrete mathematical structures
628 questions
Computational complexity classes and their relations
601 questions
Computational and mathematical logic.
493 questions
Questions about approximation algorithms.
452 questions
formal languages, grammars, automata theory
410 questions
general questions about selecting a best element from some set of available alternatives.
401 questions
A soft question is a question (possibly subjective) about the field of theoretical computer science as opposed to being a question in theoretical computer science.
396 questions
Quantum computation and computational issues related to quantum mechanics
372 questions
Automata Theory, including abstract machines, grammars, parsing, grammatical inference, transducers, and finite-state techniques
372 questions
Computability theory a.k.a. recursion theory.
363 questions
Circuit complexity is the study of resource-bounded circuits and the functions computed by such circuits.
349 questions
Programming languages, in particular, focussing on their semantics.
349 questions
Type structure is a syntactic discipline for enforcing levels of abstraction.
346 questions
Time complexity of decision problems or relations among time-bounded complexity classes. (Use the [analysis-of-algorithms] tag for the time taken by particular algorithms.)
343 questions
Properties and applications of data structures, such as space lower bounds, or time complexity of insertion and deletion of objects.
329 questions
Theoretical questions about Machine learning, especially Computational Learning Theory, including Algorithmic Learning Theory, PAC learning, and Bayesian Inference
323 questions
SAT stands for the Boolean satisfiability problem.
293 questions
Computational Geometry is the study of geometric problems from a computational perspective. Examples of problems include: computation of geometric objects such as convex hulls, dimensionality reductio…
268 questions
questions about lowerbounds on functions, usually the complexity of an algorithm or a problem
Theoretical aspects of cryptography and information security.
255 questions
How hard is counting the number of solutions?
239 questions
Church's formal system used in computatability, programming languages and proof theory to represent effective functions, programs and their computation, and proofs.
234 questions
Questions in probability theory
213 questions
Linear algebra deals with vector spaces and linear transformations.
206 questions
The Turing machine is a fundamental model of computation, especially in theoretical work.
204 questions
An algorithm whose behaviour is determined by its input and a generator producing uniformly random numbers.
194 questions
Questions about Boolean functions and their analysis
194 questions
Mathematical and computational method for finding the best outcome in a given mathematical model where the list of requirements is represented as linear relationships.
189 questions
The big picture tag is for a "broad, overall view or perspective of an issue or problem."
185 questions
Machine learning and learning theory: PAC learning, algorithmic learning theory, and computational aspects of Bayesian inference and graphical models.
182 questions
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