Nina Jacobson was president of a Walt Disney Company subsidiary.
In computability theory , a Specker sequence is a computable , monotonically increasing , bounded sequence of rational numbers whose supremum is not a computable real number .. computability theory. computability theory. computable. computable function. supremum. supremum. computable real number. computable real number. The first example of such a sequence was constructed by Ernst Specker -LRB- 1949 -RRB- .. Ernst Specker. Ernst Specker. The existence of Specker sequences has consequences for computable analysis .. computable. computable function. computable analysis. computable analysis. The fact that such sequences exist means that the collection of all computable real numbers does not satisfy the least upper bound principle of real analysis , even when considering only computable sequences .. computable. computable function. least upper bound principle. least upper bound principle. A common way to resolve this difficulty is to consider only sequences that are accompanied by a modulus of convergence ; no Specker sequence has a computable modulus of convergence .. computable. computable function. modulus of convergence. modulus of convergence. The least upper bound principle has also been analyzed in the program of reverse mathematics , where the exact strength of this principle has been determined .. least upper bound principle. least upper bound principle. reverse mathematics. reverse mathematics. In the terminology of that program , the least upper bound principle is equivalent to ACA0 over RCA0 .. least upper bound principle. least upper bound principle