%0 Journal Article
%@ 0165-1765
%A Bilancini, Ennio
%A Boncinelli, Leonardo
%D 2010
%F eprints:3884
%I Elsevier
%J Economics Letters
%K Normal goods; Bordered Hessian
%N 1
%P 13-15
%T Preferences and normal goods: An easy-to-check necessary and sufficient condition
%U http://eprints.imtlucca.it/3884/
%V 108
%X We provide a necessary and sufficient condition for goods to be normal when utility functions are differentiable and strongly quasi-concave. Our condition is equivalent to the condition proposed by Alarie et al. (1990), but it is easier to check: it only requires to compute the minors associated with the border column (or row) of the bordered Hessian matrix of the utility function.