Jordaan, Kerstin HeidrunWang, H.Zhou, J.2014-06-252014-09K. Jordaan, H. Wang & J. Zhou (2014) Monotonicity of zeros of polynomials orthogonal with respect to an even weight function, Integral Transforms and Special Functions, 25:9, 721-729, DOI: 10.1080/10652469.2014.904303.1065-2469 (print)1476-8291 (online)10.1080/10652469.2014.904303http://hdl.handle.net/2263/40382The monotonicity properties of all the zeros with respect to a parameter of orthogonal polynomials associated with an even weight function are studied. The results we obtain extend the work of A. Markoff. The monotonicity of the zeros of Gegenbauer, Freud-type and symmetric Meixner-Pollaczek orthogonal polynomials as well as Al-Salam-Chihara q-orthogonal polynomials are investigated. For the Meixner-Pollaczek polynomials, a special case of a conjecture by Jordaan and To´okos which concerns the interlacing of their zeros between two different sequences of Meixner-Pollaczek polynomials is proved.en© 2014 Taylor and Francis. This is an electronic version of an article published in Integral Transforms and Special Functions, vol. 25, no. 9, pp. 721-729, 2013. doi : 10.1080/10652469.2014.904303. Integral Transforms and Special Functions is available online at : http://www.tandfonline.com/loi/gitr20.Freud-type orthogonal polynomialMeixner-Pollaczek polynomialsGegenbauer polynomialsAl-Salam-Chihara polynomialsZerosMonotonicityInterlacingPostprint Article