acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

This dissertation explains how the interpretation of tax law is rule by Article 5 of the Mexican Federal Tax Code and how this article has been interpreted by scholars, tax authorities, taxpayers and courts. Traditionally, the fundamental elements of tax law have been interpreted in a strict form, which means that the interpreter has to find the literal meaning of the statute, no more. Fortunately, this criterion was superseded by Precedent 133/2002 of the Second Courtroom of the Mexican Supreme Court which is the heart of this dissertation and was the culmination of a progressive development in the field of interpretation of tax law by federal courts. In this precedent the court held that even though articles that contemplate the essential elements of a tax are of strict application, those articles could admit other methods of interpretation in order to find their meaning. This crucial criterion has been recently complemented by the same Second Courtroom, through precedent 27/2006, in which clearly states the meaning of 'strict application' and establishes that this concept must be understood not like a strict interpretation or a method of interpretation but as the result of an interpretative activity The dissertation also explains how the cited development of the criterion held by federal courts has been poorly accepted by administrative courts and by Mexican scholars. Tax authorities and tax payers have been accepted this criterion only when it is convenient for their own interests In this work the author studies how the federal courts in USA, especially the American Supreme Court of Justice, interprets tax law and what have been stated by law and by American scholars The author also compares the Mexican and the American juridical system in relation with the interpretation of law and concludes that the differences are not essential; both countries apply the same methods; the difference is that the Mexican system grants a huge deference to the letter of law and the American system to the intention of Congress Finally, the author proposes the amendment of Article 5 of the Federal Tax Code, in order to adopt the existent criteria of the Mexican Supreme Court when interpreting tax statutes / acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

This thesis is divided into two parts. In the first part (chapter 1, 2 and 3), we consider the semilinear elliptic equation$$\Delta u+k(x)u-f(x,u)=0\leqno(0.1)$$on a n-dimensional complete noncompact Riemannian manifold ($M,g$). In the special case that $f(x,u)=K(x)u\sp{p},\ p={n+2\over n-2},n\geq3$, this equation becomes the well known Yamabe's equation$$\Delta u+k(x)u-K(x)u\sp{p}=0\leqno(0.1)\sp\prime$$and it is originated from the problem of prescribing scalar curvature on Riemannian manifolds. Numerous works have been done by many authors for (0.1)' We will study equation (0.1) with the assumption that $f(x,u)\ \geq\ 0$ is essentially positive and satisfies some minor growth conditions in the $u$ variable. Equation (0.1) is well adapted to the super and subsolution method. In other words, the local elliptic analysis has been well understood. Our main purpose here is to provide a global analysis of the equation (0.1) and to establish a general scheme for the problem of existence and nonexistence of positive solutions of the equation (0.1) The existence problem is essentially reduced to the existence of a positive subsolution which is easy to produce in reality if a solution ever exists. Some nonexistence results are proved by applying the maximum principle if $f(x,u)$ decays to zero not too fast in the $x$ variable near infinity. As an example, we give sharp existence and nonexistence results of equation (0.1) on $R\sp{n},n\ \geq\ 3$ In the second part (chapter 4), we study the problem of prescribing Gaussian curvature on $R\sp2$. It is well known that a continuous function $K(x)$ on $R\sp2$ is a conformal Gaussian curvature function if and only if there is a $C\sp2$ solution $u$ of the nonlinear equation$$\Delta u\ +\ K(x)e\sp{2u} = 0.\leqno(0.2)$$We prove that every continuous nonnegative radial function $K(x)\ =\ K\sb1(\vert x\vert)$ on $R\sp2$ is a conformal Gaussian curvature function. In particular, this indicates that the 2-dimensional case (prescribing Gaussian curvature) is essentially different from the problem of prescribing scalar curvature in higher dimensions since not every positive radially symmetric function on $R\sp{n}$ is a conformal scalar curvature function as is indicated by W. M. Ni in $\lbrack22\rbrack$ / acase@tulane.edu