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Ameneh Farhadian

Publications and source records attributed to Ameneh Farhadian.

8 recordsLinked to original sources

Goldbach Conjecture: Violation Probability and Generalization to Prime-like Distributions

Due to the distribution of primes among integers, we establish an upper bound for the probability $\mathbb{P}_n$ that the Goldbach conjecture fails. Assuming the conjecture holds true for all even number less than $2N$, we prove this probability is less than $e^{-N^α}$, where $ α= 1 - \frac{2\ln\ln N}{\ln N}$. For large $N$, this probability becomes vanishingly small, effectively precluding the existence of counterexamples in practice. If $N =4 \times 10^{18}$, the probability of a counterexample is less than $e^{-10^{15}}$. Our approach fundamentally depends on the distributional properties of primes rather than their primality per se. This perspective enables a natural generalization of the conjecture to non-prime subsets of integers that exhibit similar distributional characteristics. As a concrete example, we construct new subsets by applying random $\pm 1$ shifts to primes, which preserve the essential prime-like distributional properties. Computational verification confirms that this generalized Goldbach conjecture holds for all even integers up to $2 \times 10^{8}$ within these modified subsets.

math.NT↗

A Simple Explanation for the Goldbach Conjecture

In this paper, a simple explanation for the Goldbach Conjecture is given. We have shown that the probability of violating the conjecture not only for the prime numbers, but also for any subset of natural numbers whose distribution is similar to the prime numbers is negligible. This result makes it possible to generalize the conjecture to any subset of natural numbers whose distribution is similar to the prime numbers. Additionally, we selected several new subsets whose distribution amongst the natural numbers are similar to the prime numbers by randomly addition of +1 and -1 to the prime numbers and checked the Goldbach conjecture for every even integer less than $2 \times 10^8$ by computer. As it was expected, the Goldbach conjecture holds true for these new reconstructed sets, as well. Consequently, the conjecture can be generalized to any subset of natural numbers whose distribution is similar to the prime numbers. That is "being prime" is not necessary for the conjecture to hold for the instances. This fact brings to mind the idea that perhaps what makes the Conjecture to hold for the instances is "probability", not number theory facts.

math.NT↗

A Simple Algorithm for a Computationally Hard Problem

Graph isomorphism problem is a known hard problem. In this paper, a novel randomized algorithm is proposed for this problem which is very simple and fast. It solves the graph isomorphism problem with running time O(n^2.373) for any pair of n-vertex graphs whose adjacency matrices are not strongly co-det. Strongly co-det pair of matrices have very special symmetric structure which can be disarranged to be not strongly co-det by manipulating one element of the matrices.

math.CO↗

A Simple Explanation for the Reconstruction of Graphs

The graph reconstruction conjecture states that all graphs on at least three vertices are determined up to isomorphism by their deck. In this paper, a general framework for this problem is proposed to simply explain the reconstruction of graphs. Here, we do not prove or reject the reconstruction conjecture. But, we explain why a graph is reconstructible. For instance, the reconstruction of small graphs which have been shown by computer, is explained in this framework. We show that any non-regular graph has a proper induced subgraph which is unique due to either its structure or the way of its connection to the rest of the graph. Here, the former subgraph is defined an anchor and the latter a connectional anchor, if it is distinguishable in the deck. We show that if a graph has an orbit with at least three vertices whose removal leaves an anchor, or it has two vertices whose removal leaves an anchor with the mentioned condition in the paper, then it is reconstructible. This simple statement can easily explain the reconstruction of a graph from its deck.

math.CO↗

A Coordinate System for Graphs

In this paper, a function on any pair of graphs is defined whose properties are similar to the properties of dot product in vector space. This function enables us to define graph orthogonality and, also, a new metric on isomorphism classes of $n$-vertex graphs. Using dot product of graphs, a coordinate system for graphs is provided which benefits us in graph isomorphism and related problems.

math.CO↗

Almost every $n$-vertex graph is determined by its $3 \log_2{n}$-vertex subgraphs

The paper shows that almost every $n$-vertex graph is such that the multiset of its induced subgraphs on $3 \log_2{n}$ vertices is sufficient to determine it up to isomorphism. Therefore, for checking the isomorphism of a pair of $n$-vertex graphs, almost surely the multiset of their $3 \log_2{n}$-vertex subgraphs is sufficient .

math.CO↗

Discrimination of Graph Isomorphism Classes by Continuous Spectrum and Split Technique

The graph isomorphism problem is a main problem which has numerous applications in different fields. Thus, finding an efficient and easy to implement method to discriminate non-isomorphic graphs is valuable. In this paper, a new method is introduced which is very simple and easy to implement, but very efficient in discriminating non-isomorphic graphs, in practice. This method does not need any heuristic attempt and based on the eigenvalues of a new matrix representation for graphs. It, almost always, separates non-isomorphic $n$-vertex graphs in time $O(n^3)$ and in worst cases such as strongly regular graphs, in time $O(n^4)$. Here, we show that this method, successfully, characterizes the isomorphism classes of studied instances of strongly regular graphs (up to 64 vertices). Strongly regular graphs are believed to be hard cases of the graph isomorphism problem.

math.CO↗

Reconstruction of graphs via asymmetry

Any graph which is not vertex transitive has a proper induced subgraph which is unique due to its structure or the way of its connection to the rest of the graph. We have called such subgraph as an anchor. Using an anchor which, in fact, is representative of a graph asymmetry, the reconstruction of that graph reduces to a smaller form of the reconstruction. Therefore, to show that a graph is reconstructible, it is sufficient to find a suitable anchor that brings us to a solved form of the problem. An orbit O of a graph G which makes G\ O to be an anchor or two vertices which makes G \{v,w} to be an anchor with the conditions that will be mentioned, is sufficient to show that G is reconstructible. For instance, this fact is enough to show that trees are reconstructible.

math.CO↗