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Journal of Marketing 1980

Comment…

David I Schoenfeld1; Francis E. McLaughlin2

1 Consumer Advocate J.C. Penney Company, Inc. New York, NY · 2 Associate Director U. S. Office of Consumer Affairs

Abstract

In Ndogmo (2008 J. Phys. A: Math. Theor. 41 025207), the author claims to have determined a complete list of functionally independent differential invariants up to order 2 for the equivalence group of differential equations defined by vector fields when there are two and three independent variables. In this comment, we show that this is not the case. Using the equivariant moving frame method, we derive a complete set of functionally independent differential invariants of orders 1 and 2 for an arbitrary number n 2 of independent variables. In the particular case n = 2, we obtain six functionally independent invariants, two of which were not found in Ndogmo (2008 J. Phys. A: Math. Theor. 41 025207). In the case n = 3, we get 21 functionally independent invariants, six of which are new. We also give a complete classification of the differential invariants. PACS number: 02.20.Tw Mathematics Subject Classification: 58A20, 58H05, 58J70

DOI
10.1177/002224298004400203
Sources
semanticscholar openalex

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