1. Activities of Formal Methods
The main activities of Formal methods are,
Writing a formal specification
Proving properties about the specification
Constructing a program by mathematically manipulating the specification
Verifying a program by mathematical argument

2. Key points
Formal system specification complements informal specification techniques
Formal specifications are precise and unambiguous. They remove areas of doubt in a specification
Formal specifications force an analysis of the system requirements at an early stage. That helps us in correcting errors at this stage is cheaper than modifying a delivered system

3. Key points
Formal specification techniques are most applicable in the development of critical systems and standards.
Algebraic techniques are suited to interface specification where the interface is defined as a set of object classes
Model-based techniques model the system using sets and functions. This simplifies some types of behavioural specification

4. 7 Myths of Formal Methods Anthony Hall – IEEE Software Sept. 1990
Formal methods can guarantee that software is perfect.
They work by proving that programs are correct.
Only highly critical systems benefit from their use.
They involve complex mathematics.
They increase the cost of development.
They are incomprehensible to clients.
Nobody uses them for real projects.

5. Limitations to Formal Methods
Use formal methods as supplements to quality assurance methods not a replacement for them
Useful for consistency checks, but formal methods cannot guarantee the completeness of a specifications
Formal methods must be fully integrated with domain knowledge to achieve positive results

6. Acceptance of formal methods
Formal methods have not become mainstream software development techniques as was once predicted
Other software engineering techniques with better quality results.
Time-to-market versus high quality
Hard to scale up to large systems
Not well-suited for specifying and analysing user interfaces and user interaction