    Sentence 1: But the- second reads like  goiifegook while the first tries to provide  some gyasic 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 second.is easy for everyone to  understand.