Adnan Karataş

Fibonacci and Lucas quaternions are deeply studied in the literature after its definition by Horadam in 1963. Binet formula, generation function, Cassini, Catalan, Honsberger, and other identities for these sequences studied in different quaternion algebra types like split quaternion algebra, dual quaternion algebra, etc. Additionally, some of the generalizations for Fibonacci and Lucas quaternions are studied like k-Fibonacci quaternions, k-Lucas quaternions, Horadam quaternions, and more. However, despite being researched intensively, the summation formulas or weighted summation formulas for these sequences are not examined thoroughly. In this study, after briefly summarizing the literature, we focused on the summation and the weighted summation formulas for the Fibonacci and the Lucas quaternions. In addition, we provided generalized weighted summation formulas for the Fibonacci and Lucas quaternions. Moreover, we calculated generalized weighted summation formulas for the double coefficient Fibonacci and double coefficient Lucas quaternions which have two Fibonacci and Lucas coefficient in every unit of the quaternion, respectively.

Fully homomorphic encryption is one of the ultimate goals of the cryptography. It is the utmost solution for data privacy. The first seeds of the concept were planted nearly fifty-five years ago. After the thesis of Gentry, first theoretic structure was ready for the researchers. In the following years many different FHE schemes were suggested, and they were vastly improved. FHE schemes have noise or error added to the system in order to make the schemes secure, actually post quantumly secure in some cases. But this noise should be arranged regularly, not to be preponderated over the data. The core mechanism of the FHE is bootstrapping, which regulates the noise and enables us to do homomorphic operations without losing the decryption of plaintext. In this study, we collected research articles from reputable databases and reviewed them. By doing so, we make it easier to keep up with the latest advancements in bootstrapping of FHE schemes. Our goal is to provide a valuable resource for anyone with background seeking to stay up-to-date on the latest developments in the bootstrapping procedure of FHE schemes. Also, we sought answers to our research questions. Lastly, we gave open problems for related studies.

This paper introduced the concept of dual Leonardo numbers to generalize the earlier studies in harmony and establish key formulas, including the Binet formula and the generating function. Both were employed to obtain specific elements from the sequence. Moreover, we presented a range of identities that provided deeper insights into the relationships within this numerical family, such as the Cassini and d'Ocagne identities, along with various summation formulas.

In this study, we introduce the complex Leonardo numbers and give some of their properties including Binet formula, generating function, Cassini and d’Ocagne’s identities. Also, we calculate summation formulas for complex Leonardo numbers involving complex Fibonacci and Lucas numbers.

In this work, we investigated bicomplex Pell and Pell-Lucas numbers. We defined generating function and various identities involving both bicomplex Pell and Pell-Lucas numbers.

We studied both the double cross product and the bicrossproduct constructions for the Hom-Hopf algebras of general $(\alpha,\beta)$-type. This allows us to consider the universal enveloping Hom-Hopf algebras of Hom-Lie algebras, which are of $(\alpha,{\rm Id})$-type. We show that the universal enveloping Hom-Hopf algebras of a matched pair of Hom-Lie algebras form a matched pair of Hom-Hopf algebras. We observe also that, the semi-dualization of a double cross product Hom-Hopf algebra is a bicrossproduct Hom-Hopf algebra. In particular, we apply this result to the universal enveloping Hom-Hopf algebras of a matched pair of Hom-Lie algebras to obtain Hom-Lie-Hopf algebras.

In this work, we made a generalization that includes all bicomplex Fibonacci-like numbers such as; Fibonacci, Lucas, Pell, etc.. We named this generalization as bicomplex Horadam numbers. For bicomplex Fibonacci and Lucas numbers we gave some additional identities. Moreover, we have obtained the Binet formula and generating function for bicomplex Horadam numbers for the first time. We have also obtained two important identities that relate the matrix theory to the second order recurrence relations.

In this paper, first we define Horadam octonions by Horadam sequence which is a generalization of second order recurrence relations. Also, we give some fundamental properties involving the elements of that sequence. Then, we obtain their Binet-like formula, ordinary generating function and Cassini identity.