Formal Methods

Reviews on formal Semantics and Commonsense — In this post, I already introduced the philosophical traditions regarding commonsense. While commonsense reasoning is an ongoing research topic in natural language processing, there is an older approach to it that fits better some of those philosophical schools: the approach consists of deriving formal semantics from linguistic logicism. …

Abstract Vending Machines are automated machines that dispense selling products such as snacks, beverages, tickets, etc. It is vital to save time and reduce human effort. These vending machines are developed in the way of Non-IoT based and IoT-based methods. These Non-IoT based machines are not formally modeled and verified. Many…

It’s not obvious how to know things about the world, but knowing that critical systems will work correctly is a matter of duty for the engineers who work on them. How can we get beyond uncertainty into a realm of being reasonably certain that the systems we build will work…

This month, I’m challenging myself to complete an online university lecture series in Introduction to Model Checking. The course is taught by Joost-Pieter Katoen, one of the authors of Principles of Model Checking. Katoen notes that the course is focused on theory more than application. However, since I have a…

Don’t worry … it’s super easy 🙃 As some of you know, I’ve been working on a programming language and compiler. More specifically Fault is a language for modeling systems that compiles down to SMT. SMT is a form of logic programming that helps you reason about the design and…

I’ve recently been playing with the Lean Theorem Prover. I am impressed with how some of the mathematics community decided to extend this project via mathlib and really make proving theorems in this framework easy and enjoyable. Normally one of the most frustrating parts of theorem proving is having to…

Warning: extractcounterexample is a new flag in Dafny and the command to extract it will likely change Dafny is a program verifier made by Microsoft. The programmer specifies the pre and post conditions and Dafny will try to verify that the codebase meets those specifications. One of its coolest features…

Loop invariants are one of the more complicated concepts in Hoare Logic. One might say that we can simply unroll the loop, but there are many loops where we don’t know the number of iterations in advanced. Therefore, we often consider what is called the loop invariant. These are statements…

In the recitations that I’m giving for Principles of Software, we are going over reasoning through code using Hoare Logic and the program verifier Dafny. Microsoft Research designed Dafny to be similar to writing imperative code. The main difference is that you need to supply (pre/post)-conditions and the code to…