mac (01/29/83)
Hebrew Cardinal Numbers The number Aleph[2] is the next cardinal greater than Aleph[1], and so on for all the Alephs. The next higher infinity (infinite cardinal) after integers (Aleph[0]) is Aleph[1]. The cardinality of reals is sometimes called Beth[1]. It can be shown to be 2^Aleph[0] (using the definition of infinite exponents) = cardinality(powerset of integers). Beth[1] >= Aleph[1]. However, it cannot be shown that Beth[1] = Aleph[1]. Nor than the contrary be shown. This is independent of the axioms of set theory. The assumption that Beth[1] = Aleph[1] is the "Continuum Hypothesis". In general, defining Beth[0] =: Aleph[0] and Beth[i+1] =: 2^Beth[i], the "General Continuum Hypothesis" ("G.C.H") states that (i>=0) -> Beth[i] = Aleph[i]. Cardinality of n-Space While it's true as Mr. King demonstrated that there are maps R <-> R^n, there are no continuous maps. In other words, all such maps involve similar trickery. Ham Sandwiches An anectode about Russel comes to mind. He once noted that a contradiction anywhere in mathematics coule be used to prove anything (use proof by contradiction). Someone challanged him "if one and one are one, prove you're the pope". Proof was as follows: (i) I am one. (ii) The pope is one. (iii) If one and one are one, the pope and I are one. (iv) I must be the pope.