Rachit Nigam

Commoditize the Complement of Your Research

March 13, 2021

“Commoditize your complement” is an idea about how companies can build profitable markets without complete vertical integration or monopolization. I highly recommend "Laws of Tech: Commoditize Your Complement" for a more in-depth look into this idea. Very briefly, the idea is this: every product has a substitute and a complement. A substitute is a product that provides the same functionality and therefore competes with your product. For example, Zoom is a substitute for Skype. A complement is product that people buy along with your product. For example, operating systems complement personal computers. So, what can researchers learn from creating markets?

The Complement of Your Research

Some of my favorite research projects have an interesting characteristic: instead of competing with people in a hot research area, these projects build the infrastructure that everyone needs to use. Over time, such projects win out in terms of research impact and ability to do novel research because everyone who does research in that area ends up using these tools.

Let me use a particular research tool as an example. Rosette is an embedded language in Racket that allows researchers to quickly develop solver-aided tools. Solver-aided tools are a “hot topic” in programming languages research. The high-level idea is encoding the semantics of a program into boolean (or richer logics) and using SMT solvers like Z3 to either verify programs or automatically synthesize them from specifications. James Bornholt's introduction to program synthesis provides a good overview of the area.

Roughly speaking, anyone who attempts to build a solver-aided tool has to do three things: encode the semantics of programs as SMT, repeatedly query the SMT solver, and transform the output of the SMT solver back to the input language. Before languages like Rosette, researchers would spend a lot of time building compilers to painstakingly transform programs to SMT, debugging problems with the encodings, and transforming the output from the SMT solver. Every researcher who wants to build a solver-aided tool would redo this work or build upon someone else’s unmaintained research code.

The idea with Rosette is simple—build a framework where you can write an interpreter for your language and automatically turn it into a solver-aided tool. This simple idea is, of course, built upon deep insights about how solvers and symbolic execution work. I recommend reading the Rosette paper for those interested. The original Rosette paper was a novel and interesting contribution, therefore justifying its publication. However, the real research impact of Rosette has been from its continued use long after the paper was published.

As of writing this blog post, the Rosette project page outlines 19 research projects that use it in some capacity. An important reason for this is because the Rosette authors continued to maintain Rosette, provide support, and build upon the original work. However, these things only help if there a demand for a tool like Rosette—if people didn’t care about building solver-aided tools, Rosette would not be as successful.

Rosette is a successful example of the “commoditize your complement” principle—instead of competing with people working in a “hot area”, build infrastructure that boosts the productivity of the people in that area. This way, your work becomes foundational and people can more productively focus on advancing the state-of-the-art using it.

Building on Success

A long-term benefit of building tools that complement a research area is that your tools and systems become legitimate grounds for follow-up research. Generally speaking, it is hard to motivate a research project where you solve a problem for your made-up system. However, if even dozens of other groups use your system, you can both reasonably claim that the follow-up work is important and other people’s work to evaluate your follow-up work.

SymPro, a tool built upon Rosette, is an example of this. SymPro is a symbolic profiler for Rosette. Put simply, it profiles programs written in Rosette and finds code that causes the SMT encoding of a program to blow up. SymPro was able to use the existing Rosette ecosystem to develop a robust tool and evaluate it on code written by users of Rosette. This is both a value-add for users of Rosette and a compelling case to justify the research paper. The research contributions of the paper are not tied to Rosette. However, building upon Rosette makes the paper that much more compelling.

Finding a Complement

Rosette was not the first tool to address the needs of a particular research community. LLVM, Valgrind, KLEE, the Click modular router, GEM5 etc. all found research areas where people were desperate to build tools but had no good infrastructure. All of them capitalized on this need by building robust tools and providing support. So, the valuable takeaway from this is that research projects that seek to support instead of compete might win out in the long-term.

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