This paper presents a new dynamic file organization scheme based on hashing. The hash functions used here, being defined by extended hash indicator tables (EHITs), are both dynamic and perfect. The allocated storage space can be enlarged and shrunk without reorganizing the data file. Simulation results show'that the storage utilization is approximately equal to 70% in an experiment where the nu...

‎We call a ring $R$ right generalized semiperfect if every simple right $R$-module is an epimorphic image of a flat right $R$-module with small kernel‎, ‎that is‎, ‎every simple right $R$-module has a flat $B$-cover‎. ‎We give some properties of such rings along with examples‎. ‎We introduce flat strong covers as flat covers which are also flat $B$-covers and give characterizations of $A$-perfe...

Shall We Kill or Enslave Caesar? Analyzing the Caesar Model When a society overthrows a ruler – call the ruler Caesar – what determines whether Caesar is killed or enslaved? This paper presents a model of killing versus enslaving Caesar, based on a new theory which unifies justice, status, and power. The model pertains to societies which value ordinal goods like bravery, yielding predictions fo...

We present the status of formal methods at our university, and describe our course on formal software verification in more detail. We report our experiences in using Perfect Developer for the course assignments.

Randomised techniques allow very big language models to be represented succinctly. However, being batch-based they are unsuitable for modelling an unbounded stream of language whilst maintaining a constant error rate. We present a novel randomised language model which uses an online perfect hash function to efficiently deal with unbounded text streams. Translation experiments over a text stream...

The Stein-Lovász Theorem can be used to get existence results for some combinatorial problems using constructive methods rather than probabilistic methods. In this paper, we discuss applications of the Stein-Lovász Theorem to some combinatorial set systems and arrays, including perfect hash families, separating hash families, splitting systems, covering designs, lotto designs and ∆-free systems...

—The African diaspora to the Americas was one of plants as well as people. European slavers provisioned their human cargoes with African and other Old World useful plants, which enabled their enslaved work force and free maroons to establish them in their gardens. Africans were additionally familiar with many Asian plants from earlier crop exchanges with the Indian subcontinent. Their efforts e...

Neighborhood-perfect graphs form a subclass of the perfect graphs if the Strong Perfect Graph Conjecture of C. Berge is true. However, they are still not shown to be perfect. Here we propose the characterization of neighborhood-perfect graphs by studying minimal non-neighborhood-perfect graphs (MNNPG). After presenting some properties of MNNPGs, w e show that the only MNNPGs with neighborhood i...

2 Algorithm for Fp, p > 2 2 2.1 Alternate formulation of Chernoff bound . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 Returning to proof of Theorem 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.3 Digression on Perfect Hashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.4 Finishing proof of Theorem 1 . . . . . . . . . . . . . . . . . . . . . . . ...