(mathematics) An irrational constant that is the concatenation of "0." with the base-10 representations of the prime numbers in order, i.e. approximately 0.235711131719232931374143...

(mathematics) A mathematical constant, denoted by Λ, defined via the zeros of a certain function H(λ, z), where λ is a real parameter and z is a complex variable. H has only real zeros if and only if λ ≥ Λ. The Riemann hypothesis is equivalent to the conjecture that Λ ≤ 0.