Abstract:
Let be an injective function. For a vertex labeling f, the induced edge labeling is defined by, or ; then, the edge labels are distinct and are from . Then f is called a root square mean labeling of G. In this paper, we prove root square mean labeling of some degree splitting graphs.

Abstract:
A scheme for the generation of non-classical pairs of photons in atomic vapours is proposed. The scheme exploits the fact that the cross correlation of the emission of photons from the extreme transitions of a four-level cascade system shows anti-bunching which has not been reported earlier and which is unlike the case of the three level cascade emission which shows bunching. The Cauchy-Schwarz inequality which is the ratio of cross-correlation to the auto correlation function in this case is estimated to be $10^3-10^6$ for controllable time delay, and is one to four orders of magnitude larger compared to previous experiments. The choice of Doppler free geometry in addition to the fact that at three photon resonance the excitation/deexcitation processes occur in a very narrow frequency band, ensures cleaner signals.

Abstract:
We study resonance flourescence in a four level ladder system and illustrate some novel features due to quantum interference and atomic coherence effects. We find that under three photon resonant conditions, in some region of the parameter space of the rabi frequencies $\Omega_1,\Omega_2,\Omega_3$, emission is dominantly by the level 4 at the line center even though there is an almost equal distribution of populations in all the levels. As one increases $\Omega_3$ with $\Omega_1 and \Omega_2$ held fixed, the four level system 'dynamically collapses' to a two level system. The steady state populations and the the resonance flourescence from all the levels provide adequate evidence to this effect.

Abstract:
Absorption profile of a four-level ladder atomic system interacting with three driving fields is studied perturbatively and analytical results are presented. Numerical results where the driving field strengths are treated upto all orders are presented. The absorption features is studied in two regimes, i) the weak middle transition coupling, i.e. $\Omega_2 << \Omega_{1,3}$ and ii) the strong middle transition coupling $\Omega_2 >>\Omega_{1,3}$. In case i), it is shown that the ground state absorption and the saturation characteristics of the population of level 2 reveal deviation due to the presence of upper level couplings. In particular, the saturation curve for the population of level 2 shows a dip for $\Omega_1 = \Omega_3$. While the populations of levels 3 and 4 show a maxima when this resonance condition is satisfied. Thus the resonance condition provides a criterion for maximally populating the upper levels. A second order perturbation calculation reveals the nature of this minima (maxima). In the second case, I report two important features: a) Filtering of the Aulter-Townes doublet in the three-peak absorption profile of the ground state, which is achieved by detuning only the upper most coupling field, and b) control of line-width by controlling the strength of the upper coupling fields. This filtering technique coupled with the control of linewidth could prove to be very useful for high resolution studies.

Abstract:
The family of semi-stable laws is shown to be semi-selfdecomposable. Thus they qualify to model stationary first order autoregressive schemes. A connection between these autoregressive schemes with semi-stable marginals and semi-selfsimilar processes is given.

Abstract:
The structure of stationary first order max-autoregressive schemes with max-semi-stable marginals is studied. A connection between semi-selfsimilar extremal processes and this max-autoregressive scheme is discussed resulting in their characterizations. Corresponding cases of max-stable and selfsimilar extremal processes are also discussed.

Abstract:
We discuss semi-selfdecomposable laws in the minimum scheme and characterize them using an autoregressive model. Semi-Pareto and semi-Weibull laws of Pillai (1991) are shown to be semi-selfdecomposable in this scheme. Methods for deriving this class of laws are then attempted from the angle of randomization. Finally, discrete analogues of these results are also considered.

Abstract:
A transformation of gamma max-infinitely divisible laws viz. geometric gamma max-infinitely divisible laws is considered in this paper. Some of its distributional and divisibility properties are discussed and a random time changed extremal process corresponding to this distribution is presented. A new kind of invariance (stability) under geometric maxima is proved and a max-AR(1) model corresponding to it is also discussed.

Abstract:
The notion of random self-decomposability is generalized here. Its relation to self-decomposability, Harris infinite divisibility and its connection with a stationary first order generalized autoregressive model are presented. The notion is then extended to $\mathbf{Z_+}$-valued distributions.