A practical method is presented that permits retrieval from a table in constant time. The method is suitable for large tables and consumes, in practice, O(n) space for n table elements. In addition, the table and the hashing function can be constructed in O(n) expected time. Variations of the method that offer different compromises between storage usage and update time are presented.

Americans are immigrants—people whose origins are various but whose destinies made them American. Immigration—voluntary or involuntary—is what created all multiracial and multicultural nations. The United States is a prime example. Sometimes the migrants moved freely from the area of origin to the area of destination. Such was the experience of the European immigrants. Sometimes their movement ...

An ordered minimal perfect hash table is one in which no collisions occur among a prede ned set of keys, no space is unused and the data are placed in the table in order. A new method for creating ordered minimal perfect hash functions is presented. It creates hash functions with representation space requirements closer to the theoretical lower bound than previous methods. The method presented ...

This paper examines the environmental experiences of middle and working class whites and people of color in the United States during the 19 th and 20 th centuries. It examines their activism and how their environmental experiences influenced the kinds of discourses they developed. The paper posits that race, class, and gender had profound effects on people's environmental experiences, and conse...

Korner [7] defined the notion of graph-entropy. He used it in [8] to simplify the proof of the Fredman-Komlos lower bound for the family size of perfect hash functions. We use this information theoretic notion to obtain a general method for formula size lower bounds. This method can be applied to low-complexity functions for which the other known general methods ([11, 12, 3] and see also [17] )...

Minimal perfect hash functions are used for memory efficient storage and fast retrieval of items from static sets. We present an infinite family of efficient and practical algorithms for generating order preserving minimal perfect hash functions. We show that almost all members of the family construct space and time optimal order preserving minimal perfect hash functions, and we identify the on...

in this work, we investigate the transfer of some homological properties from a ring $r$ to its amalgamated duplication along some ideal $i$ of $r$ $rbowtie i$, and then generate new and original families of rings with these properties.

let $p$ be a prime number and $n$ be a positive integer. the graph $g_p(n)$ is a graph with vertex set $[n]={1,2,ldots ,n}$, in which there is an arc from $u$ to $v$ if and only if $uneq v$ and $pnmid u+v$. in this paper it is shown that $g_p(n)$ is a perfect graph. in addition, an explicit formula for the chromatic number of such graph is given.