C-semigroups on Banach spaces and functional inequalities
Let F be a filtration andbe a random time. Let G be the progressive enlargement of F with. We study the following formula, called the optional splitting formula: For any G-optional process, there exists an F-optional process and a function defined on [0∞] × (ℝ × ) being ℬ[0,∞]⊗x1d4aa;(F) measurable, such that Y=Y′1[0,τ)+Y′′(τ)1[τ,∞). (This formula can also be formulated for multiple random times ...
Let be a regular continuous positively recurrent Markov process with state space ℝ, scale function and speed measure . For ∈ℝ denote +=sup≥ (], +∞[)(()−()), −=sup≤ (]−∞; [)(()−()). It is well known that the finiteness of ± is equivalent to the existence of spectral gaps of generators associated with . We show how these quantities appear independently in the study of the exponential moments of hitting times of . Then...
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