All generalisations within logic involve inverting implication. Yet, ever since Plotkin's work in the early 1970's methods of generalising rst-order clauses have involved inverting the clausal subsumption relationship. However , even Plotkin realised that this approach was incomplete. Since inversion of subsumption is central to many Inductive Logic Programming approaches, this form of incomple...

Abstract. In this paper we explore finite rank perturbations of unilateral weighted shifts Wα. First, we prove that the subnormality of Wα is never stable under nonzero finite rank pertrubations unless the perturbation occurs at the zeroth weight. Second, we establish that 2-hyponormality implies positive quadratic hyponormality, in the sense that the Maclaurin coefficients ofDn(s) := detPn [(W...

In the current article we present a fast and reliable algorithm for evaluating nth order pentadiagonal determinants in linear time. It is a natural generalization of the DETGTRI algorithm [M. El-Mikkawy, A fast algorithm for evaluating nth order tri-diagonal determinants, J. Comput. Appl. Math. 166 (2004) 581–584]. The algorithm is suited for implementation using computer algebra systems (CAS) ...

The convolution in R with |x|−n is a very singular operator. Endowed with a proper normalization, and regarded as a limit of Riesz potentials, it is equal to Dirac’s distribution δ. However, a different normalization turns the non-linear operator: Ef = exp( −2 |Sn−1| |x|−n ∗ f), into a remarkable transformation. Its long history (in one dimension) and some of its recent applications in higher d...

In this paper, a new notion of frames is introduced: $ast$-operator frame as generalization of $ast$-frames in Hilbert $C^{ast}$-modules introduced by A. Alijani and M. A. Dehghan cite{Ali} and we establish some results.

Let M be a compact, connected surface, possibly with a finite set of points removed from its interior. Let d, n P N, and let € M be a d-fold covering space of M. We show that the covering map induces an embedding of the nth braid group BnpMq of M in the dnth braid group Bdnp€ Mq of € M, and give several applications of this result. First, we classify the finite subgroups of the nth braid group ...

where B = (bn)n≥1 is a one-column matrix and X the unknown, see [1, 2, 3, 4, 5, 6, 7, 8, 10]. Equation (1.2) can be written in the form AX = B, where AX = (An(X))n≥1. In this paper, we will also consider A an operator from a sequence space into another sequence space. A Banach space E of complex sequences with the norm ‖‖E is a BK space if each projection PnX = xn is continuous for all X ∈ E. A...