Suppose that the statement: "There is no smallest positive decimal number." is false.
Suppose the negation is true.
There IS a smallest positive decimal number.
That smallest positive decimal number is N.N > 0 [since N is a positive]
N < n [for every positive decimal number, since N is the greatest]
0 < N/2 < N N/2 is a positive decimal number and it is smaller then N.
This contradicts the supposition that N < n for every positive decimal number
N/2 is < N, so the supposition is false and the statement is true.
Does this qualify as a proof?
The statement "N > n [for every positive decimal number, since N is the greatest]" should have been " N < n [for every positive decimal number n, since N is the smallest]"