Gordon David Plotkin, FRS, FRSE (born 9 September 1946) is a theoretical computer scientist in the School of Informatics at the University of Edinburgh. Plotkin is probably best known for his introduction of structural operational semantics (SOS) and his work on denotational semantics. In particular, his notes on A Structural Approach to Operational Semantics were very influential.

Plotkin was elected a Fellow of the Royal Society in 1992, is a Fellow of the Royal Society of Edinburgh and a Member of the Academia Europæa. He is also a winner of the Royal Society Wolfson Research Merit Award. Plotkin received the 2012 Royal Society Milner Award for “his fundamental research into programming semantics with lasting impact on both the principles and design of programming languages.”[19]

His nomination for the Royal Society reads:

Plotkin has contributed to Artificial Intelligence, Logic, Linguistics and especially to Computer Science. In AI he worked on hypothesis-formation and universal unification; in Logic, on frameworks for arbitrary logics; in Linguistics, on formalising situation theory. His main general contribution has been to establish a semantic framework for Computer Science, especially programming languages. Particular significant results are in the lambda-calculus (elementary models, definability, call-by-value), non-determinism (powerdomain theory), semantic formalisms (structured operational semantics, metalanguages), and categories of semantic domains (coherent, pro-finite, concrete). Further contributions concern the semantic paradigm of full abstraction, concurrency theory (event structures), programming logic and type theory.

(from https://en.wikipedia.org/wiki/Gordon_Plotkin)