In this paper we classify all extremal and -extremal binary self-dual codes of length 38. There are exactly 2744 extremal self-dual codes, two -extremal codes, and 1730 -extremal codes. We obtain our results from the use of a recursive algorithm used in the recent classification of all extremal self-dual codes of length 36, and from a generalization of this recursive algorithm for the shadow. T...

We present an exact five-dimensional ($5D$) rotating regular black hole metric, with a deviation parameter $k\geq 0$, that interpolates between the $5D$ Kerr ($k=0$) and Kerr-Newman ($r \gg k$). This is solution of general relativity coupled to nonlinear electrodynamics. Interestingly, for given value $k$ there exits critical angular momentum $a=a_E$ which corresponds extremal degenerate horizo...

We apply the Keski-Vakkuri, Kraus and Wilczek (KKW) generalized analysis to a magnetic stringy black hole solution to compute its temperature and entropy. The solution that we choose in the Einsteindilaton-Maxwell theory is the dual solution known as the magnetic black hole solution. Our results show that the expressions of the temperature and entropy of this non-Schwarzschild-type black hole a...

Starting with the Taub–NUT solution to Einstein’s equations, together with a constant dilaton, a dyonic Taub–NUT solution of low energy heterotic string theory with non–trivial dilaton, axion and U(1) gauge fields is constructed by employing O(1, 1) transformations. The electromagnetic dual of this solution is constructed, using SL(2, IR) transformations. By an appropriate change to scaled vari...

A compact hyperbolic surface of genus g is said to be extremal if it admits an extremal disc, a disc of the largest radius determined only by g. We discuss how many extremal discs are embedded in non-orientable extremal surfaces of genus 6. This is the final genus in our interest because it is already known for g = 3, 4, 5, or g > 6. We show that non-orientable extremal surfaces of genus 6 admi...

Abstract—In this paper we classify all extremal and s-extremal binary self-dual codes of length 38. There are exactly 2744 extremal [38, 19, 8] self-dual codes, two s-extremal [38, 19, 6] codes, and 1730 s-extremal [38, 19, 8] codes. We obtain our results from the use of a recursive algorithm used in the recent classification of all extremal self-dual codes of length 36, and from a generalizati...

This work deals with the problem of the Stationary Discrete Extremal Fuzzy Dynamic System (SDEFDS) identification and briefly discusses the results developed by G. Sirbiladze [10]–[17]. Applying the results of [10] and [11], the fuzzy process with possibilistic uncertainty, the source of which is expert knowledge reflections, is constructed [12]. The dynamics of SDEFDS is described. Based on th...

It is shown that Einstein-Yang-Mills-dilaton theory has a countable family of static globally regular solutions which are purely magnetic but uncharged. The discrete spectrum of masses of these solutions is bounded from above by the mass of extremal Gibbons-Maeda solution. As follows from linear stability analysis all solutions are unstable.

We show that Einstein-Yang-Mills-dilaton theory has a countable family of static globally regular solutions which are purely magnetic but uncharged. The discrete spectrum of masses of these solutions is bounded from above by the mass of extremal Gibbons-Maeda solution. Linear stability analysis shows that all solutions are unstable. *) On leave of absence from Institute of Physics, Jagellonian ...

We discuss string theory α corrections to charged near-extremal black 3-branes/black holes in type IIB supergravity. We find that supersymmetric global AdS5 × S geometry is not corrected to leading order in α, while charged or non-extremal black 3-branes/black hole geometries receive α corrections. Following gauge theory-string theory correspondence the thermodynamics of these geometries is map...