Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
Updated
Source: published paper, printed p. 413 (PDF p. 3), the proof of Theorem 2. The source reports a Maple evaluation checked with GP/PARI, but does not supply its program. The independent implementation here evaluates an elementary upper bound for the same expression.
Certified statement and replay
Use
The exact root from Theorem 1 lies in
The certificate proves every domain condition of that theorem, shows and , and gives an upper bound on its error constant with
The upper-bound expression is approximately . This decimal is illustrative only; the strict comparison in (1) is performed on integers.
The parameter file and standard-library checker make the calculation portable. From the repository root:
uv run --no-sync python library/primes/dusart_1999_kth_prime_lower_bound/evidence/verify_dusart1999.py --output library/primes/dusart_1999_kth_prime_lower_bound/evidence/output/dusart1999_replay.jsonThe script also works from another directory when its absolute path is used;
the optional output path above lies in the owner's ignored evidence/output/,
and without it nothing is written. Stdout carries one line per named
obligation and a summary line before the JSON, whose exit_code equals the
process exit status; any failed obligation exits nonzero, including under
python -O. The interval arithmetic uses only Python's standard library,
with the check harness from the root tools package of the repository
environment; the script neither runs downloaded author code nor builds a
proof assistant. Expected runtime is about one second.
Full computer-assisted proof
Let . The integer pair represents the real interval . A rational number is enclosed by . Addition and subtraction use the appropriate endpoints. Multiplication takes the minimum and maximum of the four endpoint products and rounds outward. Division does the same with the four endpoint quotients after checking that the denominator interval is positive. These operations remain valid for signed numerators.
For a nonnegative argument, the integer-root routine returns only after verifying . Applying that check to and supplies an enclosing interval for an th root. No approximate root is accepted without these exact inequalities.
The transcendental evaluations also have explicit rational remainders:
- Write a positive logarithm argument as with , using integer comparisons. For ,
After terms the omitted sum is at most . The same formula at encloses . The checker uses , keeping the remainder even when it is smaller than one interval unit.
- Normalize a nonnegative exponential argument by powers of two so it lies in . After the Taylor terms through degree , its positive remainder is at most
The ratio bound follows because all subsequent term ratios are at most . The checker takes , squares back the required number of times, and uses for negative arguments.
- Machin's identity reduces to two alternating rational series. In each case the next term bounds the remainder after the first 240 terms. The identity follows from the tangent addition formula and the fact that lies in and has tangent one.
Monotonicity allows logarithms and exponentials to be evaluated at the two interval endpoints. Every series operation and every later operation uses directed integer rounding.
For root isolation, the checker encloses at both rational endpoints displayed above and verifies
It also checks that this interval lies above . Since there, the specified root is inside it. This proves a statement about the elementary function only. The separate assertion and the zero verification remain external.
Next the checker constructs and every coefficient of Theorem 1. It checks and , and verifies
Thus exactly, and the second line of simplifies to . It substitutes the full integral upper bounds for , using and positive coefficients. No quadrature or unbounded tail truncation is used.
Finally, it encloses this explicit upper-bound expression and checks its upper endpoint is strictly below the rational target in (1). The output's integral-bound intervals enclose the elementary upper expressions, not the exact integrals from below. Likewise, the recorded two-sided interval encloses , while the source's is only asserted to be at most that upper expression. This distinction avoids presenting a one-sided bound as an exact evaluation.
The same checker verifies the finite endpoint inequalities used in the range calculations. Those checks concern only elementary real functions. It does not enumerate primes through , verify zeta zeros, or reprove the external explicit-formula theorem.