wiki_research

personal research wiki
git clone https://a3nm.net/git/wiki_research/
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commit d47d04dc69b5b70d520b7d1e4cf281fbc90127f2
parent 35f58ef7ca014ac90cfd2f7ca643fe105776bc13
Author: Antoine Amarilli <a3nm@a3nm.net>
Date:   Thu, 30 Oct 2025 12:10:01 +0100

commit with codex

Diffstat:
algorithms | 2++
antichain | 2++
bridge | 6++++--
connected_component | 6+++++-
cut_vertex | 9+++++++++
graph_basic_notions | 2++
graph_biconnected | 9+++++++++
graph_connected | 2+-
graph_cubic | 2+-
graph_partition_edges | 7+++++--
path_graph | 2++
strong_bridge | 7+++++++
strong_orientation | 11+++++++++++
strongly_connected | 2+-
vertex_deletion | 2++
word | 2+-
16 files changed, 64 insertions(+), 9 deletions(-)

diff --git a/algorithms b/algorithms @@ -8,6 +8,8 @@ Type: - [algorithm_combinatorial] - [algorithm_randomized] - [greedy_algorithm] +- [graph_algorithms] +- [text_algorithms] By date: - [algorithms_recent]: a choice of recent algorithms on major [computational_problem] diff --git a/antichain b/antichain @@ -3,3 +3,5 @@ In a [poset], an *antichain* is a subset of elements that are pairwise [incomparable] Up: [partial_order] + +See also: [antichain_coverage] diff --git a/bridge b/bridge @@ -2,8 +2,10 @@ https://en.wikipedia.org/wiki/Bridge_(graph_theory) -An [edge] of a graph whose [edge_removal] increases the number of [connected_components] of the [graph] +An [edge] of a [graph] whose [edge_removal] increases the number of [connected_components] of the [graph] -See also: [graph_bridgeless], [bridge_set] +Variant: [strong_bridge] in [directed_graphs] + +See also: [graph_bridgeless], [bridge_set], [cut_vertex] Up: [edge] diff --git a/connected_component b/connected_component @@ -2,9 +2,13 @@ An [equivalence_class] of the [reachability] [equivalence_relation] in an [undirected_graph] +Variants: + - [weakly_connected_component] +- [strongly_connected_component] +- [biconnected_component] -See also: [strongly_connected_component], [graph_connected] +See also: [graph_connected] Up: [graph_basic_notions] diff --git a/cut_vertex b/cut_vertex @@ -0,0 +1,9 @@ +# Cut vertex + +A *cut vertex* in a [graph] is a [vertex] whose [vertex_removal] increases the number of [connected_components] of the [graph] + +Up: [bridge] + +See also: [biconnected_component] + +Aliases: cut vertices, articulation point, articulation points diff --git a/graph_basic_notions b/graph_basic_notions @@ -3,6 +3,8 @@ - [degree] - [connected_component] - [connectivity] + - [graph_connected] + - [graph_biconnected] - [strongly_connected] - [strongly_connected_component] - [path] diff --git a/graph_biconnected b/graph_biconnected @@ -0,0 +1,9 @@ +# Biconnected graph + +A *biconnected graph* is an [undirected_graph] which is [connected] and has no [cut_vertex] + +Up: [graph_basic_notions] + +Aliases: biconnected graph, biconnected graphs + +See also: [biconnected_component], [block_cut_tree] diff --git a/graph_connected b/graph_connected @@ -2,7 +2,7 @@ A [graph] ([directed_graph] or [undirected_graph]) having only one [connected_component] -See also: [strongly_connected_graph] +See also: [strongly_connected_graph], [graph_biconnected] Up: [graph] diff --git a/graph_cubic b/graph_cubic @@ -8,4 +8,4 @@ Up: [maximal_degree] Aliases: cubic graph, cubic graphs -See also: [degree_3_graph], [graph_cube] +See also: [degree_3_graph], [graph_cube], [subcubic_graph] diff --git a/graph_partition_edges b/graph_partition_edges @@ -2,8 +2,11 @@ Partitioning the edges of a [graph] into specified patterns -- [dyer1985complexity] [np_hard] to partition into [connected] [subgraphs] of size 3 even in case of [planar_graphs], and other results -- [bulteau2016decomposing]: also in the case of [graph_cubic] +- [dyer1985complexity] [NP_hard] to partition into [connected] [subgraphs] of size 3 even in case of [planar_graphs], and other results +- [bulteau2016decomposing]: also in the case of [cubic_graphs] +- Partitioning into [P3] is in [PTIME], it can be done by reduction to [perfect_matching] + - Also discussed in [diwan2015p3] + - In fact for simple undirected graphs a solution always exist when the connected components have an even number of edges, see [diwan2017decomposing] Variant: partitioning the vertices, see [graph_partition] diff --git a/path_graph b/path_graph @@ -20,3 +20,5 @@ special case: Up: [graph] See also: [path] + +Aliases: path graphs diff --git a/strong_bridge b/strong_bridge @@ -0,0 +1,7 @@ +# Strong bridge + +A *strong bridge* is an [edge] in a [directed_graph] whose [edge_removal] increases the number of [strongly_connected_components] of the [graph] + +See [cairo2023cut] + +Up: [bridge] diff --git a/strong_orientation b/strong_orientation @@ -0,0 +1,11 @@ +# Strong orientation + +https://en.wikipedia.org/wiki/Strong_orientation + +Given an [undirected_graph] G, a *strong orientation* of G is a [graph_orientation] G' of G which is a [strongly_connected_graph] + +The corresponding [computational_problem] can be solved in [linear_time], but counting the strong orientations is [sharpP_complete] + +Up: [strongly_connected] + +See also: [Transitive_orientation] diff --git a/strongly_connected b/strongly_connected @@ -6,4 +6,4 @@ Up: [mathematics] -See also: [connected] +See also: [connected], [strong_orientation] diff --git a/vertex_deletion b/vertex_deletion @@ -3,3 +3,5 @@ Removing a [vertex] from a [graph], and doing [edge_removal] of all [edges] that are [incident] to the removed [vertex] Up: [graph_modification] + +Aliases: vertex removal diff --git a/word b/word @@ -25,6 +25,6 @@ Special cases: Up: [formal_language_theory] -See also: [update_word], [sequence] +See also: [update_word], [sequence], [text_algorithms] Aliases: words, string, strings