Metamath Proof Explorer


Theorem ltapi

Description: Ordering property of addition for positive integers. (Contributed by NM, 7-Mar-1996) (New usage is discouraged.)

Ref Expression
Assertion ltapi C𝑵A<𝑵BC+𝑵A<𝑵C+𝑵B

Proof

Step Hyp Ref Expression
1 dmaddpi dom+𝑵=𝑵×𝑵
2 ltrelpi <𝑵𝑵×𝑵
3 0npi ¬𝑵
4 pinn A𝑵Aω
5 pinn B𝑵Bω
6 pinn C𝑵Cω
7 nnaord AωBωCωABC+𝑜AC+𝑜B
8 4 5 6 7 syl3an A𝑵B𝑵C𝑵ABC+𝑜AC+𝑜B
9 8 3expa A𝑵B𝑵C𝑵ABC+𝑜AC+𝑜B
10 ltpiord A𝑵B𝑵A<𝑵BAB
11 10 adantr A𝑵B𝑵C𝑵A<𝑵BAB
12 addclpi C𝑵A𝑵C+𝑵A𝑵
13 addclpi C𝑵B𝑵C+𝑵B𝑵
14 ltpiord C+𝑵A𝑵C+𝑵B𝑵C+𝑵A<𝑵C+𝑵BC+𝑵AC+𝑵B
15 12 13 14 syl2an C𝑵A𝑵C𝑵B𝑵C+𝑵A<𝑵C+𝑵BC+𝑵AC+𝑵B
16 addpiord C𝑵A𝑵C+𝑵A=C+𝑜A
17 16 adantr C𝑵A𝑵C𝑵B𝑵C+𝑵A=C+𝑜A
18 addpiord C𝑵B𝑵C+𝑵B=C+𝑜B
19 18 adantl C𝑵A𝑵C𝑵B𝑵C+𝑵B=C+𝑜B
20 17 19 eleq12d C𝑵A𝑵C𝑵B𝑵C+𝑵AC+𝑵BC+𝑜AC+𝑜B
21 15 20 bitrd C𝑵A𝑵C𝑵B𝑵C+𝑵A<𝑵C+𝑵BC+𝑜AC+𝑜B
22 21 anandis C𝑵A𝑵B𝑵C+𝑵A<𝑵C+𝑵BC+𝑜AC+𝑜B
23 22 ancoms A𝑵B𝑵C𝑵C+𝑵A<𝑵C+𝑵BC+𝑜AC+𝑜B
24 9 11 23 3bitr4d A𝑵B𝑵C𝑵A<𝑵BC+𝑵A<𝑵C+𝑵B
25 24 3impa A𝑵B𝑵C𝑵A<𝑵BC+𝑵A<𝑵C+𝑵B
26 1 2 3 25 ndmovord C𝑵A<𝑵BC+𝑵A<𝑵C+𝑵B