Eigenvector Centrality

Bayes' Theorem is a fundamental concept in probability theory that describes how to update the probability of a hypothesis based on new evidence. It mathematically expresses the idea of conditional probability, showing how the probability $P(H | E)$ of a hypothesis $H$ given an event $E$ can be calculated using the formula:

In this equation:

• $P(H | E)$ is the posterior probability, the updated probability of the hypothesis after considering the evidence.
• $P(E | H)$ is the likelihood, the probability of observing the evidence given that the hypothesis is true.
• $P(H)$ is the prior probability, the initial probability of the hypothesis before considering the evidence.
• $P(E)$ is the marginal likelihood, the total probability of the evidence under all possible hypotheses.

Bayes' Theorem is widely used in various fields such as statistics, machine learning, and medical diagnosis, allowing for a rigorous method to refine predictions as new data becomes available.

Prim's Algorithm is a greedy algorithm used to find the minimum spanning tree (MST) of a weighted, undirected graph. The algorithm starts with a single vertex and grows the MST by adding the smallest edge that connects a vertex in the tree to a vertex outside the tree. This process continues until all vertices are included in the tree. The steps of Prim's Algorithm can be summarized as follows:

1. Initialization: Begin with an arbitrary vertex, marking it as part of the MST.
2. Edge Selection: Identify the minimum weight edge connecting the vertices in the MST to those outside of it.
3. Update: Add this edge and the connected vertex to the MST.
4. Repeat: Continue selecting the minimum edge until all vertices are included.

The efficiency of Prim's Algorithm can be improved using data structures like a priority queue, resulting in a time complexity of $O(E \log V)$, where $E$ is the number of edges and $V$ is the number of vertices.

The Big O notation is a mathematical concept that is used to analyse the running time or memory complexity of algorithms. It describes how the runtime of an algorithm grows in relation to the input size $n$. The fastest growth factor is identified and constant factors and lower order terms are ignored. For example, a runtime of $O(n^2)$ means that the runtime increases quadratically to the size of the input, which is often observed in practice with nested loops. The Big O notation helps developers and researchers to compare algorithms and find more efficient solutions by providing a clear overview of the behaviour of algorithms with large amounts of data.

The Minimax Search Algorithm is a decision-making algorithm used primarily in two-player games, such as chess or tic-tac-toe. Its purpose is to minimize the possible loss for a worst-case scenario while maximizing the potential gain. The algorithm works by constructing a game tree where each node represents a game state, and it alternates between minimizing and maximizing layers, depending on whose turn it is.

In essence, the player (maximizer) aims to choose the move that provides the maximum possible score, while the opponent (minimizer) aims to select moves that minimize the player's score. The algorithm evaluates the game states at the leaf nodes of the tree and propagates these values upward, ultimately leading to the decision that results in the optimal strategy for the player. The Minimax algorithm can be implemented recursively and often incorporates techniques such as alpha-beta pruning to enhance efficiency by eliminating branches that do not need to be evaluated.

Granger Causality Tests are statistical methods used to determine whether one time series can predict another. The fundamental idea is based on the premise that if variable $X$ Granger-causes variable $Y$, then past values of $X$ should contain information that helps predict $Y$ beyond the information contained in past values of $Y$ alone. The test involves estimating two regressions: one that regresses $Y$ on its own lagged values and another that regresses $Y$ on both its own lagged values and the lagged values of $X$.

Mathematically, this can be represented as:

and

If the inclusion of past values of $X$ significantly improves the prediction of $Y$ (i.e., the coefficients $\gamma_j$ are statistically significant), we conclude that $X$ Granger-causes $Y$. However, it is essential to note that Granger causality does not imply true

Mertens' function, denoted as $M(n)$, is a mathematical function defined as the summation of the reciprocals of the prime numbers less than or equal to $n$. Specifically, it is given by the formula:

where $p$ represents the prime numbers. The growth of Mertens' function has important implications in number theory, particularly in relation to the distribution of prime numbers. It is known that $M(n)$ asymptotically behaves like $\log \log n$, which means that as $n$ increases, the function grows very slowly compared to linear or polynomial growth. In fact, this slow growth indicates that the density of prime numbers decreases as one moves towards larger values of $n$. Thus, Mertens' function serves as a crucial tool in understanding the fundamental properties of primes and their distribution in the number line.