Recent content by nounou

Thanx honestrosewater, I will try writing the formulas down.

Thanx Kleinwolf, So you think i would use another function Degree(edge(X,Y)) ? But how how will I say mathematically that the sum is even Sigma Degree(edge(X,Y)) = 2*n...?

Does anyone have an idea how can we represent certain properties of a graph using second-order logic, versus fixed-point logic : like saying that a graph has an even number of edges I've been trying to find a way to solve this for the past two days ! Any help? Anyone ?

Hurkyl, to extend Ex(Dx) & AxAy((Dx & Dy) -> x = y) : Ex(Dx & Ay(Dy -> x = y). to make it represent two edges There exists at least one edges and there exists at most two edges: There exists exactly two edges: There exists two unique edges: Ex(Dx) & AxAyAz((Dx & Dy & Dz) -> x = y &...

Thanx honestrosewater. Hurkyl, any hints?

Thank uuuuu honestrosewater :smile:

Thanx Hurkyl, honestrosewater Can u help me with this: E_x ForAll_y edge(x,y) x\= y Is this wrong?

It really has. Thanx alot

Is this it ? Ex Ey Ez Ew edge(x,y), edge(z,w) ?

four. I guess, but would that mean that to represent n edges I must have 2^n variables?

Oh . I c. But how can I actually count the edges??

So is this a correct statement in first-order logic Ex Ey edge(x,y) , x=y

they contain the same edge, since my graph has only one edge Ex Ey edge(x,y) , x=y ?

I have no clue. :cry: Do u have any hints on how to express that it has 2 distinct edges ?

Yes I do. Maybe i can use ForAll_x ForAll_y : ~edge(x, y) ?