General nonasymptotic and asymptotic formulas in channel resolvability and identification capacity and their application to the wiretap channel

Several nonasymptotic formulas are established in channel resolvability and identification capacity, and they are applied to the wiretap channel. By using these formulas, the E capacities of the above three problems are considered in the most general setting, where no structural assumptions such as the stationary memoryless property are made on a channel. As a result, we solve an open problem proposed by Han and Verdu. Moreover, we obtain lower bounds of the exponents of error probability and the wiretapper's information in the wiretap channel.