National Council of Teachers of Mathematics is collaborating with JSTOR to digitize, preserve and extend access to Journal for Research in Mathematics Education. http://www.jstor.org The Codevelopment of Mathematical Concepts and the Practice of Defining Author(s): Marta Kobiela and Richard Lehrer Source: Journal for Research in Mathematics Education, Vol. 46, No. 4 (July 2015), pp. 423-454 Published by: National Council of Teachers of Mathematics Stable URL: http://www.jstor.org/stable/10.5951/jresematheduc.46.4.0423 Accessed: 10-02-2016 21:18 UTC Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/ info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. This content downloaded from 129.59.95.115 on Wed, 10 Feb 2016 21:18:04 UTC All use subject to JSTOR Terms and Conditions