TY - JOUR ID - Matkowski2009 LB - Matkowski2009 AU - Matkowski, Janusz TI - On extension of solutions of a simultaneous system of iterative functional equations ST - On extension of solutions of a simultaneous system of iterative functional equations JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2009 VL - 29 IS - 4 SP - 415 EP - 421 DO - http://dx.doi.org/10.7494/OpMath.2009.29.4.415 UR - http://dx.doi.org/10.7494/OpMath.2009.29.4.415 AB - Some sufficient conditions which allow to extend every local solution of a simultaneous system of equations in a single variable of the form \[ \varphi(x) = h (x, \varphi[f_1(x)],\ldots,\varphi[f_m(x)]),\] \[\varphi(x) = H (x, \varphi[F_1(x)],\ldots,\varphi[F_m(x)]),\] to a global one are presented. Extensions of solutions of functional equations, both in single and in several variables, play important role (cf. for instance [M. Kuczma, Functional equations in a single variable, Monografie Mat. 46, Polish Scientific Publishers, Warsaw, 1968, M. Kuczma, B. Choczewski, R. Ger, Iterative functional equations, Encyclopedia of Mathematics and Its Applications v. 32, Cambridge, 1990, J. Matkowski, Iteration groups, commuting functions and simultaneous systems of linear functional equations, Opuscula Math. 28 (2008) 4, 531-541]). KW - functional equation KW - simultaneous system of equations KW - local solution KW - extension theorem SN - 1232-9274 ER -