Recent content by S&S

The adjacency list is a simple graph list, has no any direction. If we add two possible dirctions to every edge, then, I think we got 2^15 directed graphs, since there are 15 unique edges. How about the rest of the question? I cannot figure out.

Here is an adjacency list of a graph: 1(2,4,5) 2(1,3,4,5,6,7) 3(2,5,6,7) 4(1,2,5) 5(1,2,3,4,6,7) 6(2,3,5,7) 7(2,3,5,6) How many direct graphs, can this graph generates? If cycles are not allowed, how many direct graph can we form? (The cycle is if we start from a vertex follow the dirction of...

A permutation p of the vertex set of a graph G with the property that {a,b} is an edge if and only if {p(a), p(b)} is an dege, is called an automorphism of G. Is this right? this sounds isomorphism to me.

guys you rock.

Here is the famous thing, sum of k from 1 to n is n*(n+1)/2. I'm trying to show this by recurrence equation. Then an is the sum, I have this equation: an=a(n-1)+n. It's not a*(n-1), just like this kind equations n indicates the number of the term. The charcteristic equation is r^2-r-n=0...

Here is a computer generated possibility set. 101 125 215 520 102 150 250 521 105 151 251 110 152 501 112 201 502 115 205 510 120 210 511 121 211 512

1) Except Joey and Jill, you have 9 other players. Permute these 9 players. The 9 players have 10 possible space between them, then choose 2 out of these 10 space. Then permute Joey and Jill. Multiply all these possibilities: 9!2!(10C2)=as required. 2) For this kind circular sitting problem...

thank you guys, this's what I'm talking about. However, things getting more interesting. I used to use a graph tool which based on MS Excel and it's also programed by some higher stage research students in my school. This graph tool has two modes. First is the linear fit graphing which is...

This is just a general asking. It doesn't related with my current study. If someone can point out for me, just give me more knowleges. In my class I learned the least square technique which allow us draw a best fitted line between observed depent and indepent varivables. Then I think if my...

just say cheers I'm getting better.

Let A and B be sets and Let f:A---->B be a function. Define a function G: Power set (B)------->Power (A) by declaring that, for C is part of B or equal to B: G(C)={x is element of A: f(x) is element of C} Show that G is 1-1 if and only if f is onto. :cry: Can anyone teach me this problem...