wiki_research

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commit e382e8dbb1b60350acce119915c6045b6dbda291
parent 6a3902c06284558791308770071f922c40a3546f
Author: Antoine Amarilli <a3nm@a3nm.net>
Date:   Sun, 30 Mar 2025 10:44:55 +0200

commit with codex

Diffstat:
bpp | 4+++-
circuit | 4+++-
complexity_time_classes | 21+++++++++++++++++++++
connectivity | 1+
cut | 13+++++++++++++
cut_ranked_enumeration | 10++++++++++
cutwidth_directed | 5+++++
graph_directed | 4++--
graph_minor | 2++
pathwidth_computation | 1+
ptime | 16----------------
self_reducibility | 8++++++++
tree | 1+
tree_cut_width | 5+++++
tree_weighted | 7+++++++
up | 4+++-
us | 11+++++++++++
word_automaton_exclusive | 15+++++++++++++++
18 files changed, 111 insertions(+), 21 deletions(-)

diff --git a/bpp b/bpp @@ -2,6 +2,8 @@ Class BPP: [algorithm_randomized] for [decision_problem] with [two_sided_error] can err in both directions with proba 1/4. The error probability can be made exponentially small by retrying +It is known that [PTIME] is included in BPP; the converse implication is not known + it is not known if BPP is contained in [nptime] It is known that if [nptime] subseteq BPP then in fact [nptime] = [rp] : if you have an @@ -11,7 +13,7 @@ you can remove errors on one side (uses [self_reducibility]) [sipser_lautemann_theorem]: It is known that BPP is in [sigma2_cap_pi2]: https://en.wikipedia.org/wiki/Sipser%E2%80%93Lautemann_theorem - as BPP is closed under [complementation] it suffices to show that it is in [sigma2] -Analogue [bpl] BPL with logarithmic space condition +Analogue [BPL] with logarithmic space condition Corresponding notion of [algorithm] running in [ptime]: "[monte_carlo_algorithm] with bounded probability of two-sided error" diff --git a/circuit b/circuit @@ -14,6 +14,8 @@ - [probabilistic_circuit] - [Semiring_circuit] - [formula] +- [circuit_monotone] +- [circuit_positive] ## Problems @@ -51,6 +53,6 @@ Up: [theoretical_computer_science] -See also: [sum_product_network] +See also: [sum_product_network], [formula] Aliases: circuits diff --git a/complexity_time_classes b/complexity_time_classes @@ -0,0 +1,21 @@ +# Complexity time classes + +- [ptime] / [p_complete] + - [linear_time], [linear_time_nearly], [linear_time_almost] +- [np_intermediate], cf [ladners_theorem] +- [nptime] + - [conptime] + - [np_cap_conp] +- [exptime] + - [nexptime] + - [2exptime] + - [TOWER] +- [PP] +- [PSPACE] + - [pspace_complete] +- [oplusP] +- [US] + +Up: [complexity_class], [complexity_time] + +Aliases: time complexity class, time complexity classes diff --git a/connectivity b/connectivity @@ -11,6 +11,7 @@ Problem of knowing how many edges/vertices you must remove from a [graph] in ord - [strongly_connected_graph] - [weakly_connected_graph] +- [connectivity_circuit] See also: [mengers_theorem], [minimum_cut], [connected_graph] diff --git a/cut b/cut @@ -0,0 +1,13 @@ +# Cut + +In a [graph], a *cut* is a [partition] of the [vertices] in two sets +- There may be a source s and a sink t, and then an *st-cut* is one where the source is on one side and the sink is on the other side +- The graph may be [graph_directed] or [graph_undirected] + - The correspondance to [network_flow] is in the case of [graph_directed] +- An [ideal_cut] is one where there is no [edge] at all going from the right side to the left side + +- [cut_ranked_enumeration] + +Up: [network_flow] + +Aliases: cuts, network cut, network cuts diff --git a/cut_ranked_enumeration b/cut_ranked_enumeration @@ -0,0 +1,10 @@ +# Cut ranked enumeration + +[Enumeration] of [cuts] with [polynomial_delay] + +- [picard1979structure] +- [vazirani1992suboptimal] + +Up: [ranked_enumeration] of [cut] + +See also: [beideman2022deterministic] diff --git a/cutwidth_directed b/cutwidth_directed @@ -0,0 +1,5 @@ +# Cutwidth directed + +introduced in [chudnowski2012tournament] + +Up: [cutwidth] on [directed_graphs] diff --git a/graph_directed b/graph_directed @@ -1,6 +1,6 @@ # Graph directed -A [graph] where [edges] are [directed_edges] [ordered_pairs] +A [graph] where [edges] are [directed_edges] - [directed_acyclic_graph] - [graph_period] @@ -8,6 +8,6 @@ A [graph] where [edges] are [directed_edges] [ordered_pairs] Up: [graph] -See also: [graph_undirected], [directed_edge] +See also: [graph_undirected], [directed_edge], [graph_oriented] Aliases: directed graph, directed graphs diff --git a/graph_minor b/graph_minor @@ -4,6 +4,8 @@ [graph_minor_testing] +- [graph_immersion] + Up: [graph] See also: [robertson_seymour], [topological_minor], [excluded_minor], [forbidden_minor], [induced_minor] diff --git a/pathwidth_computation b/pathwidth_computation @@ -6,6 +6,7 @@ https://en.wikipedia.org/wiki/Pathwidth#Special_classes_of_graphs - Is [NP_complete] even on [bounded_degree] [planar_graphs] - Can be computed in [linear_time] for [trees] and [forests] - Can be computed in [polynomial_time] for [treelike] [graphs] +- Is [NP_complete] on [weighted_trees], cf [mihai2009pathwidth] - [pathwidth_approximation] diff --git a/ptime b/ptime @@ -1,16 +0,0 @@ -# PTIME - -[ptime_complete] - -When the input consists of integers, we distinguish: https://en.wikipedia.org/wiki/Time_complexity#Strongly_and_weakly_polynomial_time -- "strongly polynomial" which means - - polynomial in the number of inputs - - the memory used in polynomial in the size of the input -- "weakly polynomial" meaning polynomial in the number of integers and in the log of integers, e.g., [euclidean_algorithm], not just polynomial in the number of integers -- not to be confused with [pseudo_polynomial_time]!! - -Up: [complexity_class] - -See also: [pseudo_polynomial_time], [quasipolynomial], [oplusp], [ptime_reduction] - -Aliases: P, polynomial time diff --git a/self_reducibility b/self_reducibility @@ -0,0 +1,8 @@ +# Self-reducibility + +https://en.wikipedia.org/wiki/Function_problem#Self-reducibility + +The paper [jerrum1986random] that defines it shows equivalence of [counting_approximate] and [sampling_approximate] +- it also shows that [counting_approximate] to within a constant factor allows you, for self-reducible problems, to do [counting_approximate] with a [fpras], by going via [sampling_approximate] + +Up: [theoretical_computer_science] diff --git a/tree b/tree @@ -69,6 +69,7 @@ - [polytree] - [multitree] - [out_tree] as a [directed_graph] +- [tree_weighted] Up: [data_structure] diff --git a/tree_cut_width b/tree_cut_width @@ -0,0 +1,5 @@ +# Tree cut width + +discussed in [ganian2022algorithmic] + +Up: [width_measure] diff --git a/tree_weighted b/tree_weighted @@ -0,0 +1,7 @@ +# Tree weighted + +A [tree] featuring [weights] + +Up: [tree] + +Aliases: weighted tree, weighted trees diff --git a/up b/up @@ -7,6 +7,8 @@ https://complexityzoo.net/Complexity_Zoo:U#up - on negative instances, all [runs] are rejecting - on positive instances, exactly one [run] accepts -Generalization: [FewP] +Generalizations: +- [FewP] +- [US] Up: [nptime], [unambiguity], [complexity_class] diff --git a/us b/us @@ -0,0 +1,11 @@ +# US + +https://complexityzoo.net/Complexity_Zoo:U#us + +The [complexity_time_class] of [decision_problems] definable with a [nondeterministic_PTIME_Turing_machine] that accepts when there is precisely one [accepting_run] + +It is a superset of [UP] + +Up: [complexity_time_classes] + +See also: [XNFA] diff --git a/word_automaton_exclusive b/word_automaton_exclusive @@ -0,0 +1,15 @@ +# Word automaton exclusive (XNFA) + +Like an [NFA] but accept the words for which there is precisely one [accepting_run] + +Every [UFA] is an XNFA + +[Academic_papers]: +- [kutrib2024complexity], which is about [word_automaton_exclusive_unary] +- [kutrib2023complexity] + +Related to the [time_complexity_class] [US] + +Up: [word_automaton_unambiguous] + +Aliases: XNFA