lcz

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6 years, 129 days
changsha, China

MaplePrimes Activity


These are questions asked by lcz

 I'd like to get all at most 15 vertices Non-isomorphic  connected  bipartite graphs. One way is to use the function NonIsomorphicGraphs(k, output = graphs, outputform = graph, restrictto = connected).

with(GraphTheory):

k:=8;
s1:=[NonIsomorphicGraphs(k,restrictto = connected,output=graphs,outputform=graph)]:
bipartitegraph:=select[flatten](x->IsBipartite(x)=true, s1):
nops(bipartitegraph);

But when k=9, it is slow, I doubted that the code 

By Checking out the encyclopedia,http://oeis.org/A033995 , we knew the following number of bipartite graphs datas of , at most 14, they are not many(the datas contain  no-connected conditions)

 

so I read the help document about  

awesome.

Ps: I know  in SageMath  we can get all bipartite graphs quikly even though n>=10  by  using the 

for g in graphs.nauty_geng('-c -b 10 -g'):
 
But I hope it can be realized in Maple. 

Thanks!

 

I got a list containing all non isomorphic connected graphs with 6 vertices. Total number of the list members is 112 , and they are not too many . So I want to draw them all . It is good for Maple worksheet .
 
In order to save it and print it out on paper, I import it as pdf form . But the problem is that every page in pdf only contains 8 graphs . It wastes wasted too many spaces. It is unreasonable . I want to draw 20-30 graphs in one page of pdf. What is the solution to my problems? Thanks in advance. This problem has puzzled me for a long time.

with(GraphTheory):
s1:=[NonIsomorphicGraphs(6,restrictto = connected,output=graphs,outputform=graph)]:
DrawGraph~(s1);

 

L1:=[1,2,5,6,9]:


L2:=[0,-2,5,6,9]:

  Hello,every one :

There is a recursive formula where parameters a,b,c and d are real numbers with a>=b, c>=d;

rsolve({f(n+1)-((a-1)*(b-1)+(c+d))*f(n)-c*d*f(n-1)=0, f(0)=a,f(1)=a*(b - 1)+c},f):	
simplify(%) 

Final expression is too complex, If possible,I'd like to get a more concise expression. 
The screenshots of my running results are as follows:

Thanks in advance.

        I  want save a set as shown below:
       
 E:={{1,2,3,4,5,6},{4,5,6,7,8,9,10,11},{10,11,12,13,14}};
E := {{10, 11, 12, 13, 14}, {1, 2, 3, 4, 5, 6}, {4, 5, 6, 7, 8, 9, 10, 11}}
     
    The order of set is changed; I have known the list can do it following my order,
       E:=[{1,2,3,4,5,6},{4,5,6,7,8,9,10,11},{10,11,12,13,14}];
but I want to know what can I do in set?

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