The following is adapted from a posting of Horning to the larch-interest mailing list on June 19, 1995, which was itself condensed from the preface of [Guttag-Horning93].) This project has been a long time in the growing. The seed was planted by Steve Zilles on October 3, 1973.

A good place to start is the Guttag and Horning's book [Guttag-Horning93]. (This book is sometimes called "the silver book" by Larchers.) Consider it required reading. If you find that all tough going, you might want to start with Liskov and Guttag's book [Liskov-Guttag86], which explains the background and motivates the ideas behind abstraction and specification. (See section 1.9 What is the use of formal specification and formal methods?, for more background.

According to Jim Horning (personal communication, January 20, 1998) and John Guttag (personal communication, March 28 1998): "The name was not selected at PARC (hence from the Sunset Western Garden Book), but at MIT. The project had been known informally there as 'Bicycle'." One day Mike Dertouzos [director of the MIT Laboratory for Computer Science] and John were talking on the phone.

Larch [Guttag-Horning93] may be thought of as an approach to formal specification of program modules. This approach is an extension of Hoare's ideas for program specification [Hoare69] [Hoare72a]. Its distinguishing feature is that it uses two "tiers" (or layers) [Wing83]. The top tier is a behavioral interface specification language (BISL), tailored to a specific programming language. Such BISLs typically use pre- and postcondition specifications to specify software modules.

The two "tiers" used in the Larch family of specification languages are LSL, which is called the bottom tier, and a behavioral interface specification language (a BISL), which is called the top tier. This specification of program modules using two "tiers" is a deliberate design decision (see [Wing83] and [Guttag-Horning93], Chapter 3).

The main difference between LSL and a Larch BISL is that in LSL one specifies mathematical theories of the operators that are used in the pre- and postcondition specifications of a Larch BISL. Thus LSL is used to specify mathematical models and auxiliary functions, and the a Larch BISL is used to specify program modules that are to be implemented in some particular programming language.

Like VDM-SL, Z [Hayes93] [Spivey92] (pronounced "zed") is a specification language that allows both the specification of mathematical values and program modules. Like LSL, Z allows the definition of mathematical operators equationally (see [Spivey92], section 3.2.2). A Z schema is roughly comparable to an LSL trait. The main difference between Z and LSL is that in Z specifications can include state variables.

This question might mean one of several other more precise questions. These questions are discussed below. One question is: is there a Larch-style BISL for some particular object-oriented (OO) programming language? Yes, there are Larch-style BISLs for Modula-3 (see [Guttag-Horning93], chapter 6, and [Jones91]), Smalltalk-80 (see [Cheon-Leavens94]), and C++ (see [Leavens97] [Leavens96b]).

The Larch Shared Language (LSL) (see [Guttag-Horning93], Chapter 4, and [Guttag-Horning-Modet90]) is a language for specifying mathematical theories. LSL is a kind of equational algebraic specification language [Guttag75] [Guttag-Horning78] [Goguen-Thatcher-Wagner78] [Ehrig-Mahr85] [Futatsugi-etal85] [Mosses96] [Loeckx-Ehrich-Wolf96]. That is, specifications in LSL mainly consist of first-order equations between terms.

The Larch Prover (LP) [Garland-Guttag95] is a program that helps check and debug proofs. It is not geared toward proving conjectures automatically, but rather toward automating the tedious parts of proofs. It automates equational rewriting (proofs by normalization), but does not (by default) automatically try other proof techniques. aid the debugging of specifications (i.e.

The Veterans History Project (VHP) collects and preserves the remembrances of American war veterans and civilian workers who supported them. These collections of first-hand accounts are archived in the American Folklife Center at the Library of Congress for use by researchers and to serve as an inspiration for generations to come.

It began in Corpus Christi, and has been in the Houston Texas area for approximately 5 years. Over this past year 140 babies have been saved. Texas has 56 signed parishes. The Gabriel Project is also in the Maryland and Washington area. Presentation B.V.M. (Cheltenham) and Visitation (Trooper) parishes are now signed in Penna.

Having different BISLs tailored to each programming language allows each BISL to specify all the details of a program module's interface (how to call it) and behavior (what it does). If one has a generic interface specification language, such as VDM-SL [Jones90] [ISO-VDM96] [Fitzgerald-Larsen98], then one cannot specify all interface details. The division into two tiers allows the language used for each tier to be more carefully designed and expressive.

First, a more precise comparison is needed, because Larch is not a single language, but a family of languages (see above). Another problem with this comparison is that Larch has two tiers, but VDM-SL [Jones90] [ISO-VDM96] [Fitzgerald-Larsen98], Z [Hayes93] [Spivey92], and COLD-K [Feijs-Jonkers92] are all integrated languages, which mix aspects of both of the tiers of the Larch family.

By VDM, one means, of course, the specification language VDM-SL [Jones90] [ISO-VDM96] [Fitzgerald-Larsen98]. In comparison with LSL, in VDM-SL one can specify mathematical values (models) using constructs similar to those in denotational semantics and typed, functional programming languages.

Like Larch, COLD-K [Feijs-Jonkers92] makes more of a separation into mathematical and interface specifications, although all are part of the same language. The part of COLD-K comparable to LSL is its algebraic specifications (see [Feijs-Jonkers92], Chapters 2 and 3). In contrast to LSL, COLD-K does not use classical logic, and can specify partial functions. All COLD-K types have an "undefined" element, except the type of the Booleans.

We were founded 23 years ago by Loren Crabtree, MD and Paul Keisling, MSW. The concept of PT evolved in response to years of working with young adults in a private psychiatric hospital. Many of these men and women experienced repeated cycles of complex, debilitating difficulties: The program started with one young man, an apartment, and several staff members.

The United States Congress created the Veterans History Project in 2000. The authorizing legislation (Public Law 106-380), sponsored by Representatives Ron Kind, Amo Houghton, and Steny Hoyer in the U.S. House of Representatives and Senators Max Cleland and Chuck Hagel in the U.S. Senate, received unanimous support and was signed into law by President William Jefferson Clinton on October 27, 2000.

New names do not appear instantly in the online database; please allow the VHP staff time to properly preserve, house, and catalog collection materials (presently about 4 to 6 months from the time materials are received). Information contained in the database is based on participants' own reporting of their service history.

No. We collect personal narratives from wartime veterans and those who supported them. These stories may be recorded with a video camera or a tape recorder; however, they may also be typewritten (preferably a minimum of 10 pages). We also accept original collections of diaries, letters, maps, home movies, and photographs. You are always welcome to send additional materials. Please be sure to include a note or letter indicating that you are sending an addition to your collection.

The Project is focused on first-hand accounts of veterans who served in World War I (1914-1920), World War II (1939-1946), the Korean War (1950-1955), the Vietnam War (1961-1975), the Persian Gulf War (1990-1995), or the Afghanistan and Iraq conflicts (2001-present) and on US citizen civilians who were actively involved in supporting war efforts (such as war industry workers, USO workers, flight instructors, medical volunteers, etc.).

Studies for the expansion project go back to at least 1991, which estimated the price at $41.5 million. CalTrans initiated the expansion project in 2001, which included producing a quick, cheap environmental review in lieu of a comprehensive analysis -- hoping that no one would suggest otherwise. BEC and one federal agency challenged the CalTrans environmental review, forcing the agency to create an Environmental Impact Report in 2002, which was finalized in 2003.

Based on the premise, "you can't manage what you can't measure," the University at Buffalo Regional Institute founded the State of the Region project in 1998 to monitor the Buffalo Niagara region's performance in key areas read more...

In October of 2000, NYSERNet held a retreat for members of its Boards of Directors. At the retreat, Board members asked NYSERNet to investigate the feasibility of employing dark fiber as a means for providing access to the NYSERNet network in New York City.

The ProZ.com Project History(SM) system provides translators and interpreters with a convenient means of keeping a record of projects done, by language, field and other characteristics. Use it to organize your records, keep track of payments, etc. Additionally, the Project History(SM) system allows users to display general details of select projects in their profile pages, in order to communicate to potential clients and collaborators the nature of their past experience.