Motivating example

1
Motivating example

• You want to do a cruise on the Nile
• Your electronic secretary has to book
• A return flight to Egypt
• And a cruise
• such that the cruise happens between the back and
  forth legs of your flight
• While minimizing waiting time in between.

2
Example (continued)

• Your electronic secretary deals with two travel
  agents
• Agent A, who is quick, and can do flights and
  cruises, but only one at a time
• And Agent B, who is slow and only does cruises.
• Solution
• Let agent A book the flight while agent B books
  the cruise.
• In case A finishes before B even starts, let A
  book the cruise as well.

3
Booking a flight and a cruise in parallel
Original specification
Alternative specification
4
Conclusion

• Commonly used criteria for equivalence of
  specifications are inadequate
• when the specifications are used in certain
  contexts
• For compositional verification we use carefully
  crafted notions of equivalence and implementation.

5
General research goals

• Pinpoint subtle features of concurrent systems
  that are inadequately modeled by contemporary
  techniques, leading to untrustworthy
  specifications.
• Provide reliable specification techniques through
  mathematical rigor.
• Ultimately leading to trustworthy software.