"Almost never" redirects here. For the Biota album, see Almost Never (album). For the British television series, see Almost Never (TV series).
"Probability 1" redirects here. For Rudolf Carnap's notion of "probability1", see Probability interpretations.
In probability theory, an event is said to happen almost surely (sometimes abbreviated as a.s.) if it happens with probability 1 (or Lebesgue measure 1).[1] In other words, the set of outcomes on which the event does not occur has probability 0, even though the set might not be empty. The concept is analogous to the concept of "almost everywhere" in measure theory. In probability experiments on a finite sample space with a non-zero probability for each outcome, there is no difference between almost surely and surely (since having a probability of 1 entails including all the sample points); however, this distinction becomes important when the sample space is an infinite set,[2] because an infinite set can have non-empty subsets of probability 0.
Some examples of the use of this concept include the strong and uniform versions of the law of large numbers, the continuity of the paths of Brownian motion, and the infinite monkey theorem. The terms almost certainly (a.c.) and almost always (a.a.) are also used. Almost never describes the opposite of almost surely: an event that happens with probability zero happens almost never.[3]
^Weisstein, Eric W. "Almost Surely". mathworld.wolfram.com. Retrieved 2019-11-16.
^"Almost surely - Math Central". mathcentral.uregina.ca. Retrieved 2019-11-16.
^Grädel, Erich; Kolaitis, Phokion G.; Libkin, Leonid; Marx, Maarten; Spencer, Joel; Vardi, Moshe Y.; Venema, Yde; Weinstein, Scott (2007). Finite Model Theory and Its Applications. Springer. p. 232. ISBN 978-3-540-00428-8.
In probability theory, an event is said to happen almostsurely (sometimes abbreviated as a.s.) if it happens with probability 1 (or Lebesgue measure...
converges almost completely, or almost in probability towards X. When Xn converges almost completely towards X then it also converges almostsurely to X....
Almost periodic function - and Operators Almost all Almostsurely Approximation List of mathematical jargon "Almost All Real Numbers are Transcendental -...
{ X n } {\displaystyle \{X_{n}\}} converges to X {\displaystyle X} almostsurely, it means that the set of points O = { ω ∣ lim X n ( ω ) ≠ X ( ω ) }...
complement is of measure zero. In probability theory, the terms almostsurely, almost certain and almost always refer to events with probability 1 not necessarily...
{\mathcal {N}}(0,u).} W {\displaystyle W} has almostsurely continuous paths: W t {\displaystyle W_{t}} is almostsurely continuous in t {\displaystyle t} . That...
of the following three conditions holds: (a) The stopping time τ is almostsurely bounded, i.e., there exists a constant c ∈ N {\displaystyle \mathbb...
\alpha }} has almostsurely pure point spectrum and exhibits Anderson localization. (It is known that almostsurely can not be replaced by surely.) That the...
generally, "almost all" is sometimes used in the sense of "almost everywhere" in measure theory, or in the closely related sense of "almostsurely" in probability...
{\displaystyle \mathbf {x} } and z {\displaystyle \mathbf {z} } , then almostsurely we have m ~ M , n ( x , Θ 1 , … , Θ M ) = ∑ i = 1 n Y i K M , n ( x...
flips will almostsurely converge to 1⁄2 as n approaches infinity. Although the proportion of heads (and tails) approaches 1⁄2, almostsurely the absolute...
points have infinitely many intersections almostsurely, but for dimensions higher than 5, they almostsurely intersect only finitely often. The asymptotic...
"almostsurely"—a central property of the Lebesgue integral. Basically, one says that an inequality like X ≥ 0 {\displaystyle X\geq 0} is true almost surely...
discovered to be exceptionally complex mathematically. The Wiener process is almostsurely nowhere differentiable; thus, it requires its own rules of calculus...
the cumulative distribution function of a random variable which is almostsurely 0. (See constant random variable.) In operational calculus, useful answers...
measurability theorem. A function f {\displaystyle f} is said to be almostsurely separably valued (or essentially separably valued) if there exists a...
from an almostsurely constant random variable, which may take other values, but only on events with probability zero. Constant and almostsurely constant...
name for a clade). Therefore, in practice the name Liliopsida will almostsurely refer to the usage as in the Cronquist system. In summary the monocotyledons...
{1}{t}}Y_{t}={\frac {1}{\operatorname {E} [S_{1}]}}\operatorname {E} [W_{1}]} almostsurely. Renewal processes additionally have a property analogous to the central...
decays almostsurely if β is less than a critical value β* ≈ 0.70258, known as the Embree–Trefethen constant, and otherwise grows almostsurely. They also...
the intersection of two almost sure events is almost sure. By definition, we conclude that g(Xn) converges to g(X) almostsurely. Slutsky's theorem Portmanteau...