Could somebody elaborate in details the meaning of following statement (source ):
[...] under the propositions as types correspondence, Hilbert systems correspond to combinatory logic in the same way that natural deduction/sequent calculus corresponds to lambda-calculus.
Essentially, the question reduces to in which sense in this context natural deduction corresponds/ in which sense related to lambda-calculus?
A naive guess: Can lambda- calculus be regarded as certain model/"realization" of natural deduction system?
(The question is from content related also to this one