Some faces of Smarandache semigroups' concept in transformation semigroups' approach

In the following text, the main aim is to distinguish some relations between Smarad- che semigroups and (topological) transformation semigroups areas. We will see that a transformation group is not distal if and only if its enveloping semigroup is a Smarandache semigroup. Moreover we will find a classifying of minimal right ideals of the enveloping semigroup of a transformation semigroup

Revisiting Agegraphic Dark Energy in Brans-Dicke Cosmology

We explore a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) universe which is filled with agegraphic dark energy (ADE) with mutual interaction with pressureless dark matter in the background of Brans-Dicke (BD) theory. We consider both original and new type of agegraphic dark energy (NADE) and further assume the sign of the interaction term can change during the history of the Universe. We obtain the equation of state parameter, the deceleration parameter and the evolutionary equation for the sign-changeable interacting ADE and NADE in BD theory. We find that, in both models, the equation of state parameter, $w_D$, cannot cross the phantom line, although they can predict the Universe evolution from the early deceleration phase to the late time acceleration, compatible with observations. We also investigate the sound stability of these models and find out that both models cannot show a signal of stability for different model parameters.Comment: 10 pages, 14 figure

Stability of HDE model with sign-changeable interaction in Brans-Dicke theory

We consider the Brans-Dicke (BD) theory of gravity and explore the cosmological implications of the sign-changeable interacting holographic dark energy (HDE) model in the background of Friedmann-Robertson-Walker (FRW) universe. As the system's infrared (IR) cutoff, we choose the future event horizon, the Granda-Oliveros (GO) and the Ricci cutoffs. For each cutoff, we obtain the density parameter, the equation of state (EoS) and the deceleration parameter of the system. In case of future event horizon, we find out that the EoS parameter, $w_{D}$, can cross the phantom line, as a result the transition from deceleration to acceleration expansion of the universe can be achieved provided the model parameters are chosen suitably. Then, we investigate the instability of the sign-changeable interacting HDE model against perturbations in BD theory. For this purpose, we study the squared sound speed $v_s^2$ whose sign determines the stability of the model. When $v_s^2<0$ the model is unstable against perturbation. For future event horizon cutoff, our universe can be stable (${v}^{2}_s>0$) depending on the model parameters. Then, we focus on GO and Ricci cutoffs and find out that although other features of these two cutoffs seem to be consistent with observations, they cannot leads to stable dominated universe, except in special case with GO cutoff. Our studies confirm that for the sign-changeable HDE model in the setup of BD cosmology, the event horizon is the most suitable horizon which can passes all conditions and leads to a stable DE dominated universe.Comment: 19pages, 22figure

Lifting 1/4-BPS States on K3 and Mathieu Moonshine

The elliptic genus of K3 is an index for the 1/4-BPS states of its sigma model. At the torus orbifold point there is an accidental degeneracy of such states. We blow up the orbifold fixed points using conformal perturbation theory, and find that this fully lifts the accidental degeneracy of the 1/4-BPS states with h=1. At a generic point near the Kummer surface the elliptic genus thus measures not just their index, but counts the actual number of these BPS states. We comment on the implication of this for symmetry surfing and Mathieu moonshine.Comment: 29+5 pp, a sign mistake corrected in eqs. (3.14) and (4.20), footnote 6 added to clarify this point, references adde

Interval valued intuitionistic (S,T)(S,T)-fuzzy HvH_v-submodules

On the basis of the concept of the interval valued intuitionistic fuzzy sets introduced by K.Atanassov, the notion of interval valued intuitionistic fuzzy $H_v$-submodules of an $H_v$-module with respect to $t$-norm $T$ and $s$-norm $S$ is given and the characteristic properties are described. The homomorphic image and the inverse image are investigated.In particular, the connections between interval valued intuitionistic $(S,T)$-fuzzy $H_v$-submodules and interval valued intuitionistic $(S,T)$-fuzzy submodules are discussed