A basic problem of mathematical physics is replacing a nonlinear functional equation by a more tractable (analytically and computationally) linear equation. More generally, the problem is to replace a system of non-linear equations, often derived from a single equation by means of an orthogonal expansion in a parameter with a system of linear functional equations. To treat this closure problem, the Memorandum presents a method based on the concept of relative invariants and the use of the multidimensional Lagrange expansion theorem. 16 pp.
This report is part of the RAND Corporation Research memorandum series. The Research Memorandum was a product of the RAND Corporation from 1948 to 1973 that represented working papers meant to report current results of RAND research to appropriate audiences.
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