We consider a group-theoretic analogue of the classic subset sum problem. It is known that every virtually nilpotent group has polynomial time decidable subset sum problem. In this paper we use subgroup distortion to show that every polycyclic non-virtually-nilpotent group has NP-complete subset sum problem.

We consider the problem of determining finite integer sets which are knapsack-solvable in linear time (that is, it is possible to determine in linear time, for any integer b, whether b can be expressed as a sum of distinct elements of that set) and where the largest element is as small as possible. We study the condition that the k-subsets (for fixed k) when lexicographically ordered have incre...

The data presented in this paper are reference ranges for frequencies of thirty-eight subpopulations of T, B and NK lymphocytes, established from a cohort of 253 healthy blood donors aged from 19 to 67. When relevant, the influence of age or sex was taken into account to calculate these reference values. This article is related to the research article entitled "Influence of age, sex and HCMV-se...

In this review I shall survey various properties of lymphocytes which allow clear distinctions to be drawn between different lymphocyte subsets. I shall discuss only thymus-derived (T) lymphocytes since these cells appear to play a key role in regulating the activities of other lymphoid cells (B cells and macrophages) as well as carrying out effector functions themselves. In the first section I...

uncertainty associated with mixing models is often substantial, but has not yet been fully incorporated in models. the objective of this study is to develop and apply a bayesian-mixing model that estimates probability distributions of source contributions to a mixture associated with multiple sources for assessing the uncertainty estimation in sediment fingerprinting in zidasht catchment, iran....

In this paper, we first characterize the convex $L$-subgroup of an $L$-ordered group by means of fourkinds of cut sets of an $L$-subset. Then we consider the homomorphic preimages and the product of convex $L$-subgroups.After that, we introduce an $L$-convex structure constructed by convex $L$-subgroups.Furthermore, the notion of the degree to which an $L$-subset of an $L$-ord...

This thesis explores new modifications to the successful LLL approach to solving the Subset Sum problem. This work is an optimization of the matrix representation of an instance. Traditionally, the basis matrix contained only one column with set elements and the sum. In this thesis we suggest having several data columns (thus introducing multidimensionality). This allows us to reduce the size o...

Let Zp be the finite field of prime order p and A be a subset of Zp. We prove several sharp results about the following two basic questions: (1) When can one represent zero as a sum of distinct elements of A ? (2) When can one represent every element of Zp as a sum of distinct elements of A ?

The main purpose of this paper is to introduce several concepts of the metric-like spaces. For instance, we define concepts such as equal-like points, cluster points and completely separate points. Furthermore, this paper is an attempt to present compatibility definitions for the distance between a point and a subset of a metric-like space and also for the distance between two subsets of a metr...