Past exam of the mathematics course of the University of Cambridge 2022 ii Paper 4 29K b Solution Created 2026-09-24 Updated 2026-09-25
Under a risk-neutral measure, the discounted stock must be a martingale. If is the probability of the factor , this condition issoThe hypothesis ensures , making this equivalent to the original probability measure. Since the returns are independent under , the number of up moves has a binomial distribution, and hence
Past exam of the mathematics course of the University of Cambridge 2023 iii Paper 122 4 c Solution 2026-09-28
For fixed disjoint , the random variable has the binomial distribution . A two-sided Chernoff bound givesWhen , this is at mostThere are at most ordered disjoint pairs , since each vertex can lie in , in , or in neither. The union bound therefore makes the probability of any failure at mostwhich proves the simultaneous estimate.
Past exam of the mathematics course of the University of Cambridge 2023 iii Paper 224 4 b Solution 2026-09-28
LetHere has the binomial distribution with parameters . Part a, now with independent coordinates, givesBy Pinsker's inequality, the probability mass functions therefore converge in total variation, and in particular converges in distribution to .
The joint probability of the observed row depends only on :Taking logarithms in any fixed base and choosing giveswhereThe convergence lemma supplied in the question now yieldsThis sparse triangular array therefore has a random limiting normalized self-information rather than the constant limit in the usual asymptotic equipartition property.
Past exam of the mathematics course of the University of Cambridge 2026 iii Paper 122 1 a Solution Created 2026-09-24 Updated 2026-09-25
Explore the connected component of a graph containing a fixed vertex by Breadth-first search. If the exploration discovers at least vertices, then before its th discovery at least of at most tested potential edges must be present. The tests are independent Bernoulli trials with parameter , soThe binomial distribution on the right has mean . For , the exponential Markov bound givesfor an absolute constant . The union bound over the choices of now givesTaking with makes this probability tend to zero. This proves the subcritical component bound for a binomial random graph.
Past exam of the mathematics course of the University of Cambridge 2026 iii Paper 207 3 a Solution Created 2026-09-24 Updated 2026-09-25
Under the boundary null , rejection requires both and . Independence of the two binomial distributions givesThe rejection event is increasing in , so this boundary value is the supremum over the composite null .
Rank-order expected prize allocation 2026-10-06
For players with independent valuations having a continuous distribution function , a type occupies rank when exactly rivals have higher values. Multiplying this binomial distribution by the rank prize and summing gives . Ties occur only on zero-probability events when the valuation law is atomless.
Uniform balls-in-bins allocation Created 2026-10-06 Updated 2026-10-07
Place labelled balls independently into labelled bins, each with probability . The vector of bin counts has a multinomial distribution, and each count separately has the binomial distribution . Distinct bin counts have covariance , so they are dependent for and . Counts of bins of a specified size are sums of indicator variables; their expectations follow from the linearity of expectation, without any independence between bins.
Uniform prior Created 2026-10-05 Updated 2026-10-06
A uniform prior on a finite-volume parameter region assigns constant probability density there and zero outside. On it is , giving a Beta distribution posterior after binomial distribution data. Uniformity depends on the coordinate: a nonlinear reparametrization introduces a Jacobian and generally does not preserve a uniform density.
Uniform random graph process 2026-10-07
Start with the empty graph and reveal the edges of the complete graph in a uniformly random order. After steps its edge set is a uniform -element subset. Independent uniform edge labels couple this process with all binomial random graphs: , where has a binomial distribution with parameters . For a monotone graph property, concentration of transfers a threshold estimate between edge probability and edge count.