wiki_research

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commit b60de1effc5516efdec845e641dd2064bb1cd692
parent d3cba66b4b4164ca3da9c0bb59b9d4a70a95d8e1
Author: Antoine Amarilli <a3nm@a3nm.net>
Date:   Thu, 17 Apr 2025 16:59:35 +0200

commit with codex

Diffstat:
algorithm_combinatorial | 3++-
algorithm_randomized | 2+-
batch_updates | 2++
boolean | 2++
boolean_valuation | 13+++++++++++++
enumeration_paths | 7-------
group | 6++++--
guarded_fragment | 1+
pathwidth | 2++
preprocessing | 2++
satisfying_valuation | 9+++++++++
semigroup | 1+
semigroup_cancellative | 12++++++++++++
simple_path | 6++++--
strassens_algorithm | 4+++-
triangle | 3++-
triangle_detection | 3+++
universality_automata_nondeterministic | 2++
18 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/algorithm_combinatorial b/algorithm_combinatorial @@ -1,6 +1,7 @@ # Combinatorial algorithm -Algorithms, e.g., for [matrix_multiplication] which try to exclude [strassens_algorithm], but it looks like there is not formal definition of the concept +Algorithms, e.g., for [matrix_multiplication] which try to exclude [strassens_algorithm] (and its use of [subtraction]) +- but it looks like there is not formal definition of the concept Up: [algorithms] diff --git a/algorithm_randomized b/algorithm_randomized @@ -14,6 +14,6 @@ Techniques used for randomized algorithms: Up: [algorithms] -See also: [fpras], [rp], [complexity_random], [randomness] +See also: [fpras], [rp], [complexity_random], [randomness], [derandomization] Aliases: randomized diff --git a/batch_updates b/batch_updates @@ -4,3 +4,5 @@ - [batch_update_technique]: using as a technique to design algorithms Up: [incremental_maintenance] + +Aliases: bulk updates diff --git a/boolean b/boolean @@ -5,5 +5,7 @@ - [formula_boolean] - [satisfiability_boolean] - [boolean_semiring] +- [true] +- [false] Up: [logic] diff --git a/boolean_valuation b/boolean_valuation @@ -0,0 +1,13 @@ +# Boolean valuation + +A [function] mapping a set X to [Boolean] values + +- can be used to [evaluate] a [Boolean_function] + - can be a [satisfying_valuation] of a [Boolean_function] + - or a [falsifying_valuation] + +Up: [function], [valuation], [boolean] + +See also: [boolean_function] + +Aliases: assignment, Boolean assignment, assignments, Boolean assignments diff --git a/enumeration_paths b/enumeration_paths @@ -1,7 +0,0 @@ -# Enumeration paths - -[Enumeration] of [paths] in a [graph] - -[Practice]: [peng2025hop] - -Up: [enumeration_graphs], [paths] diff --git a/group b/group @@ -10,8 +10,8 @@ Types of groups: [Theorems]: -- classification of [finite_simple_groups] -- [feit_thompson] theorem +- [Classification_of_finite_simple_groups] +- [Feit_Thompson] theorem Tools: @@ -21,3 +21,5 @@ Tools: Up: [algebraic_structure], [mathematics] See also: [monoid], [group_language] + +Aliases: groups diff --git a/guarded_fragment b/guarded_fragment @@ -3,6 +3,7 @@ - [gf2] - [gc2]: like [fo2] with [counting_quantifiers] - [gck] +- [guarded_TGD] According to [cate2023craig], enjoys [finite_model_property] but not [craig_interpolation] diff --git a/pathwidth b/pathwidth @@ -6,6 +6,8 @@ like [treewidth] but for [tree_decomposition] which is a [path] - [pathwidth_computation] - [pathwidth_approximation] +- [path_decomposition] + Up: [width_measure], [path] See also: [treewidth], [path_excentricity], [obstruction], [treelength] diff --git a/preprocessing b/preprocessing @@ -4,6 +4,8 @@ Computation done before something else Used in [enumeration_definition] +- [linear_preprocessing] + Up: [enumeration_definition] See also: [delay], [enumeration_phase] diff --git a/satisfying_valuation b/satisfying_valuation @@ -0,0 +1,9 @@ +# Satisfying valuation + +[Boolean_valuation] such that a [Boolean_function] [evaluates] to [true] + +Up: [boolean_valuation] + +Aliases: satisfying assignment, satisfying assignments + +See also: [satisfiability_boolean] diff --git a/semigroup b/semigroup @@ -6,6 +6,7 @@ Special cases: - [monoid] - [group] +- [semigroup_cancellative] Examples: diff --git a/semigroup_cancellative b/semigroup_cancellative @@ -0,0 +1,12 @@ +# Semigroup cancellative + +https://en.wikipedia.org/wiki/Cancellative_semigroup + +Only cancellative semigroups can embed into [groups], cf: +https://en.wikipedia.org/wiki/Cancellative_semigroup#Embeddability_in_groups + +Up: [semigroup] + +Aliases: cancellative semigroup, cancellative semigroups + +See also: [cancellation] diff --git a/simple_path b/simple_path @@ -1,7 +1,9 @@ # Simple path -path with no repeated vertices +A [path] with no repeated [vertices] Up: [path] -See also: [trail] +See also: [trail], [walk] + +Aliases: simple paths diff --git a/strassens_algorithm b/strassens_algorithm @@ -5,6 +5,8 @@ https://en.wikipedia.org/wiki/Strassen_algorithm multiplication of 2 by 2 matrices can be done with 7 products instead of 8 - gives an algorithm because you can reapply it recursively -works with integers, but not with [matrix_boolean] in [boolean_semiring] +works with integers, but not with [matrix_boolean] in [boolean_semiring] (or not as-is) + +uses [subtraction], so works in a [ring] but not in a [semiring]: it is not a [combinatorial_algorithm] Up: [matrix_multiplication] diff --git a/triangle b/triangle @@ -11,7 +11,8 @@ Variante: single-source triangle counting ? - [sparse_triangle] -See also: [matrix_multiplication], [ov_conjecture], [negative_triangle], [exact_triangle], [triangle_free_graph], [triangle_inequality] +See also: [matrix_multiplication], [ov_conjecture], [negative_triangle], [exact_triangle], [triangle_free_graph], [triangle_inequality], +[Loomis_Whitney] Up: [graph] diff --git a/triangle_detection b/triangle_detection @@ -9,6 +9,9 @@ https://en.wikipedia.org/wiki/Triangle-free_graph#Triangle_finding_problem - [itai1977finding] - For [sparse_graphs], it is possible to do Otilde(m^{2omega/(omega+1)}) [alon1997finding] - [triangle_detection_conjecture] +- For [combinatorial_algorithms], the best known bounds are [cubic] up to [polylogarithmic] factors, and any [truly_subcubic] algorithm would imply a [truly_subcubic] algorithm for [Boolean_matrix_multiplication] + - cf [williams2018subcubic] + - cf https://people.csail.mit.edu/virgi/6.890/lecture2.pdf Up: [computational_problem] on [graph], [conjunctive_query], [fine_grained_complexity_problems] diff --git a/universality_automata_nondeterministic b/universality_automata_nondeterministic @@ -3,6 +3,8 @@ [conp_complete] even on [unary_alphabet]: - https://cs.stackexchange.com/a/97751 +The shortest rejected word of an automaton with O(n) states may be Omega(n 2^n): cf [ellul2005regular], Theorem 32 + Up: [universality_automata], [automata_nondeterministic] Aliases: NFA universality