** Ludwig Boltzmann, Austrian physicist ( d. 1906 )

** Boltzmann entropy, an approximation to Gibbs entropy

** Chaitin's constant.

** In complex analysis, the Omega constant, a solution of Lambert's W function

** The mixing of two or more substances of the same chemistry but different concentrations to form a constant.

**, the Gelfond – Schneider constant ( Hilbert number ).

** Copowers are colimits of constant diagrams from discrete categories.

** The term is also used in data transmission to describe cases in which corresponding significant instants of two or more sequential signals have a constant phase relationship.

** T < sub > 1 </ sub >, the spin – lattice relaxation time constant used for T < sub > 1 </ sub >- weighted MRI, a form of magnetic resonance imaging

** set a register ( a temporary " scratchpad " location in the CPU itself ) to a fixed constant value

** or µ < sub > 0 </ sub > is the magnetic constant or permeability of free space ;

** or k < sub > e </ sub > is the Coulomb constant.

** Conversely, if ƒ: I → R is absolutely continuous and thus differentiable almost everywhere, and satisfies | ƒ ′( x )| ≤ K for almost all x in I, then ƒ is Lipschitz continuous with Lipschitz constant at most K.

** All money is issued for a limited period by constant value ( neither inflation, nor deflation ).

** Those who have a constant twinge of depression ( often due to political plights ) during their governance ( 在國遭憂 ) are called " Pitiful " ( 愍 mǐn ).

** Left to focus on healing and recovery from an injury received to his right foot in Thailand from a motorcycle accident in 1996 that had been hindered by constant travel and performances.

** Mitchell Feigenbaum's discovery of the Feigenbaum constant was based initially on numerical observations, followed by a rigorous proof.

** the Dissociation constant applicable to process abbreviated as " i "

** ( advanced feature ) Dial controlling the amount of steam to emit as a constant stream ;

** constant ( see also degenerate distribution ),

** Dielectric relaxation, the delay in the dielectric constant of a material

** Niven's constant, a mathematical constant

** Helmholtz free energy, the energy that can be converted into work at a constant temperature and volume

** keeping transcript levels constant / proportional to a factor

** Coulomb damping, a type of constant mechanical damping

** Steady state ( physiology ), also known as homeostasis, a system in which a particular variable is not changing but energy must be continuously added to maintain this variable constant.

** Eunectes murinus, the green anaconda, the largest species, is found east of the Andes in Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil and on the island of Trinidad.

** Eunectes notaeus, the yellow anaconda, a smaller species, is found in eastern Bolivia, southern Brazil, Paraguay and northeastern Argentina.

** Eunectes deschauenseei, the dark-spotted anaconda, is a rare species found in northeastern Brazil and coastal French Guiana.

** Eunectes beniensis, the Bolivian anaconda, the most recently defined species, is found in the Departments of Beni and Pando in Bolivia.

** Tarski's theorem: For every infinite set A, there is a bijective map between the sets A and A × A.

** The Cartesian product of any family of nonempty sets is nonempty.

** König's theorem: Colloquially, the sum of a sequence of cardinals is strictly less than the product of a sequence of larger cardinals.

** Hausdorff maximal principle: In any partially ordered set, every totally ordered subset is contained in a maximal totally ordered subset.

** For every non-empty set S there is a binary operation defined on S that makes it a group.

** Tychonoff's theorem stating that every product of compact topological spaces is compact.

** In the product topology, the closure of a product of subsets is equal to the product of the closures.

** If S is a set of sentences of first-order logic and B is a consistent subset of S, then B is included in a set that is maximal among consistent subsets of S. The special case where S is the set of all first-order sentences in a given signature is weaker, equivalent to the Boolean prime ideal theorem ; see the section " Weaker forms " below.

** Any union of countably many countable sets is itself countable.

** If the set A is infinite, then there exists an injection from the natural numbers N to A ( see Dedekind infinite ).

** Every infinite game in which is a Borel subset of Baire space is determined.

** The Vitali theorem on the existence of non-measurable sets which states that there is a subset of the real numbers that is not Lebesgue measurable.

** The Lebesgue measure of a countable disjoint union of measurable sets is equal to the sum of the measures of the individual sets.

** The Nielsen – Schreier theorem, that every subgroup of a free group is free.