Reflective Higher-Order Calculus, or Rho calculus for short, is a mathematical theory first proposed by Greg Meredith and Matthias Radestock in 2005.

Rho calculus was created as an extension of π-calculus, which is an open procedure that provides a theory of processes when provided a theory of names. Instead of this open theory, Rho calculus is a closed theory of processes, meaning that in Rho calculus the theory of names arises from and is wholly determined by the theory of processes.

Co-founder Greg Meredith worked extensively on a Microsoft's BizTalk Process Orchestration Engine, an application integration platform that implements higher-order calculus in its execution engine. Meredith then went on to found a blockchain smart contract platform based on Rholang, named Rchain.

The theory can be found in a form of asynchronous message-passing calculus built on a notion of quoting. Names represent the code of a process as an object for process manipulation. During dequoting operations, it is possible to avoid process variables while yielding high-order characteristics.

## Timeline

## People

Greg Meredith

Co-creator

Matthias Radestock

Co-creator

## Further reading

Adventures in the Rho Calculus - reinman - Medium

reinman

Web

RChain Platform Architecture -- RChain Architecture 0.9.0 documentation

Web