The reals, of course, already have an axiom system. They are a complete, linearly ordered field. This axiom system is even categorical, meaning that it completely characterizes the reals. Up to isomorphism, the reals are the only complete, linearly ordered field. Another property of axiom systems, considered to be particularly elegant ever since the birth of formal logic, is independence. In an...

In this article, I draw attention to the value of community in John Mbiti’s philosophy using his famous axiom by reconciling tension between individual and envisages. To do this, offer a reconstruction communitarian axiom: “I am because we are; since are, therefore am.” Mbiti is considered one forerunners debate African philosophy. His axiom, which describes idea Afro-communitarianism, accounts...

We propose that failures of the axiom of choice, that is, surjective functions admitting no sections, can be reasonably classified by means of invariants borrowed from algebraic topology. We show that cohomology, when defined so that its usual exactness properties hold even in the absence of the axiom of choice, is adequate for detecting failures of this axiom in the following sense. If a set X...

Ex. 17 Let us call the new system L, i.e. its axioms are all propositional tautologies (Axiom 1) plus the axioms 2> (Axiom 2) and 2φ∧2ψ → 2(φ∧ψ) (Axiom 3), and the rules modus ponens and φ→ ψ 2φ→ 2ψ We have to show that for all formulas φ `K φ ⇔ `L φ. ⇒: For this direction we have to show that L derives all axioms of K and all its rules. Axiom 1 of K is the same as Axiom 1 in L, thus we have no...

§9.1 The Axiom of Choice We come now to the most important part of set theory for other branches of mathematics. Although infinite set theory is technically the foundation for all mathematics, in practice it is perfectly valid for a mathematician to ignore it – with two exceptions. Of course most of the basic set constructions as outlined in chapter 2 (unions, intersections, cartesian products,...