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The closed curve represented by the dotted line crossing the graph corresponds to a cut of the graph.

Formally, a cut of a graph G ( V , E ) is a partition of the graph vertices into subsets V 1 , V 2 V such that V 1 V 2 = V and V 1 V 2 = , as demonstrated by [link] . The corresponding cut set is the set of edges C such that C = ( u , v ) E | u V 1 , v V 2 . Hence, the cut set induces a bipartite subgraph.

The partitions of graph vertices that correspond to this cut are highlighted in red and blue.

The size of a cut equals the sum of the weights of edges in the cut set, which in the case of unweighted graphs is simply the number of edges in the cut set. With this definition of size, the maximum cut of a graph, like those shown in [link] , is a cut not smaller than any other cut in the graph, and it corresponds to the largest bipartite subgraph of the graph. The maximum cut of a graph is not necessarily unique and is not unique in either of the examples.

Maximum cuts for the two example graphs are shown above.

Alternatively, the problem can be formulated in terms of the edges in the complement of the cut set. The complement of a set of edges that intersects every odd cycle in a graph induces a graph with no subgraphs that are odd cycles, which is therefore a bipartite graph. Thus, the complement of the minimum set of edges intersecting every odd cycle induces the largest bipartite subgraph of the graph and hence is the maximum cut set, as illustrated in [link] .

The complement of the minimum set (red) of edges intersecting all odd cycles of a graph is the maximum cut set.

Finding the maximum cut of a graph was one of the earliest problems proven to be np-complete, which, ignoring the formal details of what that means, indicates that no currently known algorithms terminate in a polynomial bounded number of operations in all cases [link] . There are, however, several types of graphs for which polynomial bounded solutions are known, such as graphs embeddable on the plane [link] . Since computing the maxcut of large graphs often requires extremely long lengths of time, randomized ρ -approximation algorithms, such as that of Goemans and Williamson, may be employed for situations in which optimality is not required and a good estimate will suffice [link] .

Applications of the maxcut problem include minimization of number of holes on circuit boards or number of chip contacts in VLSI circuit layout design, energy minimization problems in computer vision programs, and modeling of the interactions of spin glasses with magnetic fields in statistical physics [link] .

Several algorithms

The most direct and straightforward way to find maximum cuts of a graph would be to perform an exhaustive search of all bipartitions of the graph vertices. The maximum cut may be found by iterating over all distinct bipartitions of the graph vertices, summing the weights of edges connecting vertices in opposite partitions to calculate the size of the corresponding cut, comparing this value to the largest cut size previously found, and updating the maximum accordingly.

The exhaustive algorithm, which has computational complexity O ( | E | 2 | V | ) , examines the same number of bipartitions for a tree, for which the maximum cut always equals the number of edges, as it does for a complete graph on the same number of vertices. Thus, it is clear that the exhaustive algorithm is not completely satisfactory, especially for graphs with few edges relative to other graphs with a given number of vertices.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, The art of the pfug. OpenStax CNX. Jun 05, 2013 Download for free at http://cnx.org/content/col10523/1.34
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