{ "id": "0911.5019", "version": "v1", "published": "2009-11-26T07:35:46.000Z", "updated": "2009-11-26T07:35:46.000Z", "title": "A Franklin Type Involution for Squares", "authors": [ "William Y. C. Chen", "Eric H. Liu" ], "comment": "16 pages", "categories": [ "math.CO", "math.NT" ], "abstract": "We find an involution as a combinatorial proof of a Ramanujan's partial theta identity. Based on this involution, we obtain a Franklin type involution for squares in the sense that the classical Franklin involution provides a combinatorial interpretation of Euler's pentagonal number theorem. This Franklin type involution can be considered as a solution to a problem proposed by Pak concerning the parity of the number of partitions of n into distinct parts with the smallest part being odd. Using a weighted form of our involution, we give a combinatorial proof of a weighted partition theorem derived by Alladi from Ramanujan's partial theta identity. This answers a question of Berndt, Kim and Yee. Furthermore, through a different weight assignment, we find combinatorial interpretations for another partition theorem derived by Alladi from a partial theta identity of Andrews. Moreover, we obtain a partition theorem based on Andrews' identity and provide a combinatorial proof by certain weight assignment for our involution. A specialization of our partition theorem is relate to an identity of Andrews concerning partitions into distinct nonnegative parts with the smallest part being even. Finally, we give a more general form of our partition theorem which in return corresponds to a generalization of Andrews' identity.", "revisions": [ { "version": "v1", "updated": "2009-11-26T07:35:46.000Z" } ], "analyses": { "subjects": [ "05A17", "11P81" ], "keywords": [ "franklin type involution", "ramanujans partial theta identity", "combinatorial proof", "smallest part", "eulers pentagonal number theorem" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2009arXiv0911.5019C" } } }