Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
Updated
What prime-gap statistics would imply
Put . These are author-recorded comparisons of the target statements. They do not establish the conjectured prime-gap laws.
Support is stronger than existence of a distribution
Problem 234 asks for a continuous limiting distribution of . If such a distribution gives positive mass to every open interval in and to every interval , then every is a limit point, as requested by Problem 5. For , take arbitrarily small intervals about with positive mass; convergence of their frequencies gives infinitely many indices in each interval. Choose an increasing sequence of those indices. For , use instead. Since , the normalizations have the same finite limit points.
Continuity alone does not supply full support. The conditional exponential distribution reported on Problem 234 has it, but its prime-tuple hypothesis remains unproved. The unconditional positive measure and bounded-gap properties of the set of limit points do not give full support either. For example, is a proper closed subset of , has measure at least in , and meets every interval of length one. This example tests only those two consequences, not all the stronger combinatorial assertions in Merikoski's paper. Its Theorem 1 and Corollaries 2--3 were inspected at statement depth. The next test for a proposed route is positive limiting mass in an arbitrary prescribed interval. Stop if the available conclusion only bounds total measure or gaps in the set of limit points.
Two half-density inequalities do not prove infinitely many equalities
For Problem 218, let count with , let count those with , and let count equalities. Then . Thus and together imply , not . The numerical sequence alternating between and has both inequality densities and no equality; this is a logical example, not a prime-gap construction. Marginal distributions of individual gaps likewise do not determine adjacent pairs. [[../library/primes/banks_2023_ratios_consecutive_prime_gaps/_index|Banks's ratio formula]] is presented as a conjecture motivated by a heuristic, not an unconditional adjacent-gap theorem. A route must supply both the needed joint distribution and a separate reason for infinitely many exact equalities.
A second moment still leaves a power-sized distinct run
Let . Cauchy--Schwarz and the prime number theorem give , so Problem 233 asks for an upper bound of the correct order. The inspected Theorem 1 of Stadlmann is instead . Changing from prime value to index does not remove its excess power.
Even the desired bound would only give a power estimate for the length of a run of pairwise distinct gaps starting at index , the quantity in Problem 852. Distinct positive integers have sum at least . The telescoping sum of these gaps is at most . For large this first forces , and then . The run therefore ends before . Its squared gaps have sum at least , while the hypothetical bound for Problem 233 gives . Consequently
This is far above . It is a limitation of this direct moment argument, not a proof that Problem 233 could never help by another method. A useful next test must exploit local repetition or dependence beyond a global second moment; stop the bare sum-of-squares route at the displayed bound.
First occurrences and Problem 853
For a positive even integer , let , with if no such index exists. For real put . In the notation of Problem 853, is the least missing positive even gap among indices . The positivity convention matters: including zero among candidate gap sizes would make identically zero. Exactly
It follows that is equivalent to every positive even gap occurring at least once. Infinitely many occurrences of each gap would be stronger than needed. The stronger requested conclusion is equivalent to
Indeed, if , take . Eventually , so for every fixed . Conversely, fix and use (2) with . For and all sufficiently large , , so (1) gives . Integer rounding changes neither conclusion. This exact interface exposes the hard step: a subexponential upper bound for the worst first occurrence, uniform over all even . A fixed-pattern existence theorem with uncontrolled constants does not supply (2). Stop a proposed deduction if its threshold still depends ineffectively on each individual .
Adjacent near-record gaps and Problem 1137
For integer , define
Both factors in every product are bounded by , hence
Thus Problem 1137 is equivalent to . Equivalently, for every , all sufficiently large prefixes contain no adjacent pair both at least . The omitted initial undefined product and changing to an integer prefix have no asymptotic effect. This is a relative isolation assertion. A lower bound for one large gap, such as Theorem 1 of [[../library/primes/maynard_2016_large_gaps_between_primes/_index|Maynard's large-gap paper]], gives no such upper bound for adjacent products. A route must control the smaller member of every adjacent pair relative to the running maximum. Stop before inferring isolation from a single-gap construction, even if that construction substantially increases .