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B-Method

The B-Method is a method of software development based on B, a tool-supported formal method based on an abstract machine notation, used in the development of computer software.

Version
v1 · 2026-09-28 · History
Domain-specific #
8094
Domain group
Applied Sciences & Engineering
Origin domain
Computer Science & Software Engineering
Subdomains
Formal Methods, Software Engineering → Computer Science & Software Engineering

Core Idea

B-Method is treated here as the recurring computer science and information systems identity summarized by this source-grounded definition: The B-Method is a method of software development based on B, a tool-supported formal method based on an abstract machine notation, used in the development of computer software. The B-Method is a method of software development based on B, a tool-supported formal method based on an abstract machine notation, used in the development of computer software. Compared to the Z notation, B is slightly more low-level and more focused on refinement to code rather than just formal.

How would you explain it like I'm…

Plan It Exactly, Then Build It

Before building a computer program, you write down very exactly what it must do, using a special careful math language. Then, step by step, you turn that description into a real program, and special helper tools check that each step still does exactly what the description said. That way of building programs is called the B-Method.

Math Plans Turned into Code

The B-Method is a way to build computer software very carefully using math. Programmers first describe the program as an 'abstract machine' in a precise notation called B. Then they refine it, step by step, into more detailed designs and finally into real code, using the same language all the way through. Tools help check that each step stays true to the original description. It's related to another careful notation called Z, but B is more focused on actually turning the description into working code.

Refinement-Based Formal Development

The B-Method is a formal method for software development based on B, a tool-supported notation that describes software as abstract machines. Developers write a precise mathematical specification, then refine it step by step into implementation code, with tool support to check the steps. The same language covers specification, design, and programming. B is related to the Z notation, which was also created by Abrial, but B is somewhat lower-level and aimed at refinement to code rather than only specification, which makes it easier to implement a B specification correctly. Abrial also founded B-Core (UK) Limited to support the B-Toolkit, a set of tools for using B. Just using mathematics or formal notation in software isn't the B-Method; the key is this abstract-machine-based, tool-supported path from specification to code.

 

The B-Method is a software development method based on B, a tool-supported formal method built around an abstract machine notation. A system is specified as abstract machines and then developed through refinement toward executable code, with the same language serving for specification, design, and programming. B is related to the Z notation, both originated by Abrial, but B is slightly more low-level and oriented toward refinement to code rather than specification alone, making a B specification easier to implement correctly than a Z one, aided by good tool support. Abrial founded B-Core (UK) Limited to support the B-Toolkit, a collection of programming tools for the B notation, and contributed to a number of B-related projects. A positive instance must preserve the core identity of a tool-supported, abstract-machine-based formal method used to develop software; sharing the name or being generically 'formal methods' is insufficient.

Scope of Application

  • History. B has been used in major safety-critical system applications in Europe (such as the automatic Paris Métro lines 14 and 1 and the Ariane 5 rocket).

  • Atelier B. Developed by ClearSy, Atelier B is an industrial tool that allows for the operational use of the B Method to develop defect-free, proven software (formal software).

  • B-Toolkit. The B-Toolkit is a collection of programming tools designed to support the use of the B-Tool, is a set theory-based mathematical interpreter for the purposes of supporting the B-Method.

  • Documented setting. The B-Method is a method of software development based on B, a tool-supported formal method based on an abstract machine notation, used in the development of computer software.

  • History. From the late 1980s, (1949–2012) was central to the development of the B-Method, having previously also worked on the early development of the Z notation.

Clarity

A clear use of B-Method names the carrier, the operative relation, and the conditions under which the source treats the identity as present. The minimal definition is The B-Method is a method of software development based on B, a tool-supported formal method based on an abstract machine notation, used in the development of computer software.

Manages Complexity

B-Method compresses multiple computer science and information systems details into a stable diagnostic relation. The source shows both the central mechanism—b was originally developed in the 1980s by Jean-Raymond Abrial in France and the UK.—and the practical consequence—then, during a refinement step, they may pad the specification in order to clarify the goal or to turn the abstract machine more concrete by adding details about data structures.

Abstract Reasoning

  1. Type the carrier. Identify the computer science and information systems entities to which the claim applies.
  2. State the relation. Use the source-grounded identity: The B-Method is a method of software development based on B, a tool-supported formal method based on an abstract machine notation, used in the development of computer software.
  3. Check operation and conditions. B is related to the Z notation (also originated by Abrial) and supports the development of programming language code from specifications.
  4. Demand recognition evidence.

Knowledge Transfer

Within the home domain. Knowledge about B-Method transfers literally when a new case preserves the same carrier type, relation, and recognition test. B has been used in major safety-critical system applications in Europe (such as the automatic Paris Métro lines 14 and 1 and the Ariane 5 rocket). Developed by ClearSy, Atelier B is an industrial tool that allows for the operational use of the B Method to develop defect-free, proven software (formal software). Beyond the home domain.

Neighborhood in Abstraction Space

B-Method sits in a sparse region of the domain-specific corpus (81st percentile for distinctiveness): few abstractions share its structure, so a faithful description tends to retrieve it precisely.

Family — Formal Logic & Semantic Systems (18 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-10-08