@article {10.3844/jmssp.2018.151.155, article_type = {journal}, title = {A Geometric Generalization of the Planar Gale-Nikaidô Theorem}, author = {Balreira, E. Cabral}, volume = {14}, year = {2018}, month = {May}, pages = {151-155}, doi = {10.3844/jmssp.2018.151.155}, url = {https://thescipub.com/abstract/jmssp.2018.151.155}, abstract = {The Gale-Nikaidô Theorem establishes global injectivity of maps defined over rectangular regions provided the Jacobian matrix is a P-matrix. We provide a purely geometric generalization of this result in the plane by showing that if the image of each edge of the rectangular domain is realized as a graph of a function over the appropriate axis, then the map is injective. We also show that the hypothesis that the Jacobian matrix is a P-matrix is simply one way to analytically check this geometric condition.}, journal = {Journal of Mathematics and Statistics}, publisher = {Science Publications} }