    Sentence 1: But the second reads like  gobbledygook while the first tries to provide  some basic notion of what is involved and  where it is applied while, at the same time,  gently notifying users that they are going to  have to seek elsewhere for a proper definition,  the understanding of which requires far more  backgound in mathematics and logic than can  be assumed in the average user.    Sentence 2: The first definitions is much more  comprehensive.