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== View an induced subgraph ==
by Jason Grout

{{{#!sagecell
m=random_matrix(ZZ,10,density=.5)
a=DiGraph(m)

@interact
def show_subgraph(to_delete=selector(range(10),buttons=True)):
    vertices=set(range(10))
    subgraph_vertices=vertices.difference([to_delete])
    html.table([["Original", "New"],
               [plot(a,save_pos=True), plot(a.subgraph(subgraph_vertices))]],
               header=True)
}}}

{{attachment:subgraph-interact.png}}


== Animations of Graph Minors ==
by Pablo Angulo

Note: you should use "Upload" or "Create a new file" to attach to the worksheet a file called wagner.sage with the following [[interact/graph_theory/wagner.sage| content]], and then you can use the code below:

{{{#!sagecell
attach(DATA + 'wagner.sage')
graph_list = {'CompleteGraph4':graphs.CompleteGraph(4),
              'CompleteGraph5':graphs.CompleteGraph(5),
              'CompleteGraph6':graphs.CompleteGraph(6),
              'BipartiteGraph3,3':graphs.CompleteBipartiteGraph(3,3),
              'BipartiteGraph4,3':graphs.CompleteBipartiteGraph(4,3),
              'PetersenGraph':graphs.PetersenGraph(),
              'CycleGraph4':graphs.CycleGraph(4),
              'CycleGraph5':graphs.CycleGraph(5),
              'BarbellGraph(3,2)':graphs.BarbellGraph(3,2)
              }
@interact
def _(u1 = text_control(value='Does this graph'),
      g = selector(graph_list.keys(), buttons = True),
      u2 = text_control(value='have a minor isomorphic to this other graph:'),
      m = selector(graph_list.keys(), buttons = True),
      u3 = text_control(value='''? It is has, show it to me,
      with an animation with the following parameters'''),
      frames = slider(1,15,1,4, label = 'Frames per second'),
      step_time = slider(1/10,2,1/10,1, label = 'Seconds per step')):
    g = graph_list[g]
    m = graph_list[m]
    if g == m:
        html('<h3>Please select two different graphs</h3>')
        return
    try:
        a = animate_minor(g, m, frames = frames)
        a.show(delay=100*step_time/frames)
    except ValueError:
        html('''<h3>The first graph have <strong>NO</strong> minor isomorphic to the second</h3>''')

}}}
{{attachment:wagner.gif}}

Sage Interactions - Graph Theory

goto interact main page

Graph Browser

by Marshall Hampton

graph_browse.png

Automorphism Groups of some Graphs

by William Stein:

auto_graph2.png

View an induced subgraph

by Jason Grout

subgraph-interact.png

Animations of Graph Minors

by Pablo Angulo

Note: you should use "Upload" or "Create a new file" to attach to the worksheet a file called wagner.sage with the following content, and then you can use the code below:

wagner.gif

interact/graph_theory (last edited 2020-02-08 12:53:38 by chapoton)