Alappat Redux: Support for Functional Language in Software Patent Claims

16 Pages Posted: 1 Jun 2013

See all articles by Andrew Chin

Andrew Chin

University of North Carolina School of Law

Date Written: May 30, 2013


The Federal Circuit has suggested in some recent cases that any algorithm can serve as adequate structural support for a means-plus-function element in a software patent claim under § 112(f). A recent proposal by Mark Lemley fully endorses this proposition and seeks its broader application. The concept of an algorithm, however, is too slippery to serve as the basis for such a rule. In this Article, I argue that this overreliance on the algorithm concept originated in a revisionist gloss on the Federal Circuit’s 1994 Alappat decision. Informed by a closer reading of what Alappat actually has to say about claim construction under § 112(f), I propose a more stable “concrete causation” standard that is applicable to all technologies, but would be especially well-aligned with the reforms in the software field intended by Lemley’s proposal.

Keywords: patents, software patents, algorithms, means-plus-function claims, Federal Circuit, USPTO, software partnership

JEL Classification: O34

Suggested Citation

Chin, Andrew, Alappat Redux: Support for Functional Language in Software Patent Claims (May 30, 2013). UNC Legal Studies Research Paper No. 2272016. Available at SSRN: or

Andrew Chin (Contact Author)

University of North Carolina School of Law ( email )

Van Hecke-Wettach Hall
100 Ridge Road
Chapel Hill, NC 27599-3380
United States
919-962-4116 (Phone)

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