Metamath Proof Explorer


Theorem elpell14qr2

Description: A number is a positive Pell solution iff it is positive and a Pell solution, justifying our name choice. (Contributed by Stefan O'Rear, 19-Oct-2014)

Ref Expression
Assertion elpell14qr2 D A Pell14QR D A Pell1234QR D 0 < A

Proof

Step Hyp Ref Expression
1 pell14qrss1234 D Pell14QR D Pell1234QR D
2 1 sselda D A Pell14QR D A Pell1234QR D
3 pell14qrgt0 D A Pell14QR D 0 < A
4 2 3 jca D A Pell14QR D A Pell1234QR D 0 < A
5 0re 0
6 pell1234qrre D A Pell1234QR D A
7 ltnsym 0 A 0 < A ¬ A < 0
8 5 6 7 sylancr D A Pell1234QR D 0 < A ¬ A < 0
9 8 impr D A Pell1234QR D 0 < A ¬ A < 0
10 6 adantrr D A Pell1234QR D 0 < A A
11 10 lt0neg1d D A Pell1234QR D 0 < A A < 0 0 < A
12 9 11 mtbid D A Pell1234QR D 0 < A ¬ 0 < A
13 pell14qrgt0 D A Pell14QR D 0 < A
14 13 ex D A Pell14QR D 0 < A
15 14 adantr D A Pell1234QR D 0 < A A Pell14QR D 0 < A
16 12 15 mtod D A Pell1234QR D 0 < A ¬ A Pell14QR D
17 pell1234qrdich D A Pell1234QR D A Pell14QR D A Pell14QR D
18 17 adantrr D A Pell1234QR D 0 < A A Pell14QR D A Pell14QR D
19 orel2 ¬ A Pell14QR D A Pell14QR D A Pell14QR D A Pell14QR D
20 16 18 19 sylc D A Pell1234QR D 0 < A A Pell14QR D
21 4 20 impbida D A Pell14QR D A Pell1234QR D 0 < A