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New exact solutions of the discrete fourth Painlevé equation
In this paper we derive a number of exact solutions of the discrete equation
𝒳𝑛+1𝒳𝑛−1 + 𝒳𝑛(𝒳𝑛+1 + 𝒳𝑛−1) = | −2𝓏𝑛𝒳3𝑛 + (𝜂 − 3𝛿−2 − 𝓏2𝑛)𝑥2𝑛 + 𝜇2 (𝑥𝑛 + 𝓏𝑛 + 𝛾) (𝑥𝑛 + 𝓏𝑛 − 𝛾) | , (1) |
where 𝑧𝑛 = 𝑛𝛿 and 𝜂, 𝛿, 𝜇 and 𝛾 are constants. In an appropriate limit (1) reduces to the fourth Painlevé (PIV) equation
d2𝓌 d𝓏2 | = | 1 2𝓌 | ( | d𝓌 d𝓏 | ) | 2 | + | 3 2 | 𝓌3 | + | 4𝓌2 | + | 2(𝓏2 - 𝛼)𝓌 | + | 𝛽 𝓌 | , (2) |
where α and β are constants and (1) is commonly referred to as the discretised fourth Painlevé equation. A suitable factorisation of (1) facilitates the identification of a number of solutions which take the form of ratios of two polynomials in the variable 𝑧𝑛. Limits of these solutions yield rational solutions of PIV (2). It is also known that there exist exact solutions of PIV (2) that are expressible in terms of the complementary error function and in this article we show that a discrete analogue of this function can be obtained by analysis of (1).
History
Publication title
Physics Letters AVolume
194Issue
5-6Pagination
358-370ISSN
0375-9601Department/School
School of Natural SciencesPublisher
Elsevier Science BvPlace of publication
Po Box 211, Amsterdam, Netherlands, 1000 AeRights statement
Copyright 1994 Elsevier B.V.Repository Status
- Restricted