Questions tagged [max-cut]

Questions on the maximum cut problem, where one is given a graph and wants to find a subset of the vertex set such that number of edges between it and the complementary subset is as large as possible.

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20 views

Score and bound in Goemans-Williamson algorithm

I am trying to have a deeper understanding of the following implementation of the Goemans-Williamson algorithm for solving the maxcut problem. ...
23 views

Finding a cut maximizing average weight of cut edges

Just checking if this version of Max Cut is still NP-hard: Given a fully connected graph $G(V,E)$, where every vertex is connected to every other vertex, and where every edge has a weight associated ...
59 views

How to find a cut in a graph with additional constraints?

I have a complete undirected graph $G=(V,E)$ with positive non-null rational weights $c:E \to \mathbb{Q}^+_{*}$ on the edges, such that $c(v,v) = 0$ for all $v$, and a subset $C \subset V$. I would ...
306 views

Using a greedy algorithm to find a cut S which at least half of the edges cut

Let $G$ be an undirected graph. Find a greedy algorithm that finds a cut $S$ which at least half of the edges cut. I tried to think about something like choosing the vertex with the highest degree, ...
27 views

Separation guarantee in Goemans Williamson algorithm

In the original paper in Goemans-Williamson paper for max-cut, we need to sample a random vector r and we output $$S = \{i : r^{T}x_{i} \geq 0\}$$ where $x_{i}$ are column vector of a feasible ...
28 views

planar max cut graph with constrains

Given a planar graph $G=(V, E)$ I am looking for a max cut algorithm with the following conditions : some vertices are in one of the partition sets? Is the algo is still polynomial ? I mean a ...
584 views

Prove that the 2-approximation of a modified local search algorithm for max-cut is tight

Consider the following local search approximation algorithm for the unweighted max cut problem: start with an arbitrary partition of the vertices of the given graph $G = (V,E)$, and as long as you ...
358 views

How can i prove that MAX-CUT is in NP?

How can i show/explain/prove that Max-Cut is in NP? "For a graph, a maximum cut is a cut whose size is at least the size of any other cut. The problem of finding a maximum cut in a graph is known as ...
105 views

Derandomize MAX-CUT problem using $\log n$ bits

Consider the MAX-CUT problem. We can flip $n$ coins to generate a random cut, and by linearity of expectation we get that with "good probability" our cut we'll be bigger then $\frac{n}{2}$. Using ...
323 views

Complexity of finding Exact Size Cut-Sets in Bipartite Graphs

I am interested in the problem of deciding if a cut-set of a given size $k$ (i.e. the number of edges crossing the partitions is $k$) exists in a given bipartite graph (both the graph and $k$ are part ...
365 views

Reducing INDSET and MAXCUT to 3SAT

Given a graph and an integer $k$ is there an independent set larger than $k$ is INDSET problem and is there a cut larger that $k$ is the MAXCUT problem. Is there standard way to convert to 3SAT from ...
2k views

Does graph G with all vertices of degree 3 have a cut vertex?

I'm asked to draw a simple connected graph, if possible, in which every vertex has degree 3 and has a cut vertex. I tried drawing a cycle graph, in which all the degrees are 2, and it seems there is ...
374 views

solving max cut problem on a huge graph (500 x 500) using Semidefinite Programming with CVXOPT

So I am learning to do SDP relaxation on graph problems, and for this max cut problem I am given a 500*500 graph, and I am using the straightforward relaxation. $W$ is the weight matrix, $X = u u^T$ ...
200 views

Why the Goemans-Williamson's MAX-CUT algorithm relax the variables to vectors of $n-$dimension on unit sphere?

Why not to some constant like 3 or 4 dimension? I suspect that it is because Cholesky Decompostion will work only for $n \times n$ matrix $B$ where $B^TB = P$ where $P$ is a semidefinite matrix. Is it ...
579 views

Greedy max k-cut approximation algorithm

I'm trying to formulate a greedy algorithm for the Max k-cut problem: Let's have an not oriented graph $G(V,E)$, each edge $e \in E$ has its weight $w_e$. The goal of the algorithm is to divide all ...
378 views

NP hardness of partitioning a graph into two subgraphs

Given a planner graph which it's vertexes have weights and an integer, W, this graph should be partitioned into two subgraphs which sum of weights for each subgraph becomes at least W. I wanted to ...
4k views

Maximum cut using a 1/2 approximation greedy algorithm

I have the following greedy algorithm for max cut problem: Initialization: $A \leftarrow \{v_1\}$ , $B \leftarrow \{v_2\}$ For $v \in V − \{v_1, v_2\}$ do: if $d(v,A) \geq d(v,B)$ then \$B \...
1k views

Maximum flow with edge demands: can't understand the example of transition to transformed graph in the lecture notes

TL;DR: There're lecture notes about a very simple reduction from "maximum flow with edge demands problem to the maximum flow problem. But I can't get the new capacities at the picture: E.g., look at ...
68 views

Maximum One Third Cut

I want to solve the following problem (This is a homework problem. Not looking for definite or complete answers): Maximum One Third Cut: Input: An undirected graph G=(V,E) where V={1,2,...,n}, such ...
527 views

Degree Reduction in Max Cut and Vertex Cover

I have been reading Alimonti and Kann's paper "Some APX-Completeness results for cubic graphs" and I don't understand why the degree-reduction gadgets for Max Cut and Min Vertex Cover have to be ...
523 views

Relation between MAX CUT and MIN CUT

I'd like to ask a question about MAX CUT and MIN CUT on graphs with unit edge-weight. I know that MAX CUT is NP-Hard, but MIN CUT is in P (i think)? Barahona, in 1982, showed (Lemma 1) finding a cut ...
171 views

reduction of maxcut problem [duplicate]

Show that if the MAX CUT decision problem can be solved in polynomial time so can the MAX CUT optimization problem by writing an algorithm that solves the optimization problem using an algorithm for ...
2k views

Reduction from PARTITION to MAX-CUT

I am trying to prove the NP-Hardness of the MAX-CUT problem. Other sources seem to reduce from the NAE-3SAT problem, however I have been trying to reduce from PARTITION because PARTITION and MAX-CUT ...