MHB What Factors Influence the Number of Connected Components in Random Graphs?

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The discussion centers on the factors influencing the number of connected components in random graphs, particularly under the Erdős–Rényi model. It highlights that random graphs can be generated with a fixed vertex set and edges added based on a probability model, such as a 50% chance for each edge. The number of connected components is affected by the size of the vertex set, with a critical threshold probability for connectedness identified as p < (1 - ε)ln(n)/n for disconnection and p > (1 + ε)ln(n)/n for connection. As the size of the graph increases, the threshold probability for connectedness becomes very small, indicating that larger graphs are more likely to be connected. Understanding these dynamics is crucial for analyzing the structure of random graphs.
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Having a hard time with this problem. Can anyone guide me in the correct direction?

Random graphs are a fascinating subject of applied and theoretical research. These can be generated with a fixed vertex set V and edges added to the edge set E based on some probability model, such as a coin flip. Speculate on how many connected components a random graph might have if the likelihood of an edge (v1,v2) being in the set E is 50%. Do you think the number of components would depend on the size of the vertex set V? Explain why or why not.
 
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I assume the likelihood of an edge $(v_1,v_2)$ is the same for all pairs of vertices $(v_1,v_2)$, and the presence of an edge is independent of other edges. Suppose a random graph with these properties has two connected components with $m$ and $n$ vertices, respectively. There are $mn$ edges that are missing between these two components, and the probability of that is $2^{-mn}$, which is exceedingly small for large $m$, $n$.

For more details, consult Wikipedia about Erdős–Rényi model of random graph generation. It turns out that if $p<\frac{(1-\varepsilon)\ln n}{n}$ for some $\varepsilon>0$, then a random graph with $n$ vertices where the probability of an edge is $p$ will almost surely be disconnected, and if $p>\frac{(1+\varepsilon)\ln n}{n}$, then a random graph with $n$ vertices will almost surely be connected. Since $\frac{\ln n}{n}\to0$ as $n\to\infty$, the threshold probability for connectedness is very small for large graphs, certainly smaller than 0.5.
 
I was reading documentation about the soundness and completeness of logic formal systems. Consider the following $$\vdash_S \phi$$ where ##S## is the proof-system making part the formal system and ##\phi## is a wff (well formed formula) of the formal language. Note the blank on left of the turnstile symbol ##\vdash_S##, as far as I can tell it actually represents the empty set. So what does it mean ? I guess it actually means ##\phi## is a theorem of the formal system, i.e. there is a...
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