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 ( 𝐶N → ( 𝐴 <N 𝐵 ↔ ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ) )

Proof

Step Hyp Ref Expression
1 dmaddpi dom +N = ( N × N )
2 ltrelpi <N ⊆ ( N × N )
3 0npi ¬ ∅ ∈ N
4 pinn ( 𝐴N𝐴 ∈ ω )
5 pinn ( 𝐵N𝐵 ∈ ω )
6 pinn ( 𝐶N𝐶 ∈ ω )
7 nnaord ( ( 𝐴 ∈ ω ∧ 𝐵 ∈ ω ∧ 𝐶 ∈ ω ) → ( 𝐴𝐵 ↔ ( 𝐶 +o 𝐴 ) ∈ ( 𝐶 +o 𝐵 ) ) )
8 4 5 6 7 syl3an ( ( 𝐴N𝐵N𝐶N ) → ( 𝐴𝐵 ↔ ( 𝐶 +o 𝐴 ) ∈ ( 𝐶 +o 𝐵 ) ) )
9 8 3expa ( ( ( 𝐴N𝐵N ) ∧ 𝐶N ) → ( 𝐴𝐵 ↔ ( 𝐶 +o 𝐴 ) ∈ ( 𝐶 +o 𝐵 ) ) )
10 ltpiord ( ( 𝐴N𝐵N ) → ( 𝐴 <N 𝐵𝐴𝐵 ) )
11 10 adantr ( ( ( 𝐴N𝐵N ) ∧ 𝐶N ) → ( 𝐴 <N 𝐵𝐴𝐵 ) )
12 addclpi ( ( 𝐶N𝐴N ) → ( 𝐶 +N 𝐴 ) ∈ N )
13 addclpi ( ( 𝐶N𝐵N ) → ( 𝐶 +N 𝐵 ) ∈ N )
14 ltpiord ( ( ( 𝐶 +N 𝐴 ) ∈ N ∧ ( 𝐶 +N 𝐵 ) ∈ N ) → ( ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ↔ ( 𝐶 +N 𝐴 ) ∈ ( 𝐶 +N 𝐵 ) ) )
15 12 13 14 syl2an ( ( ( 𝐶N𝐴N ) ∧ ( 𝐶N𝐵N ) ) → ( ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ↔ ( 𝐶 +N 𝐴 ) ∈ ( 𝐶 +N 𝐵 ) ) )
16 addpiord ( ( 𝐶N𝐴N ) → ( 𝐶 +N 𝐴 ) = ( 𝐶 +o 𝐴 ) )
17 16 adantr ( ( ( 𝐶N𝐴N ) ∧ ( 𝐶N𝐵N ) ) → ( 𝐶 +N 𝐴 ) = ( 𝐶 +o 𝐴 ) )
18 addpiord ( ( 𝐶N𝐵N ) → ( 𝐶 +N 𝐵 ) = ( 𝐶 +o 𝐵 ) )
19 18 adantl ( ( ( 𝐶N𝐴N ) ∧ ( 𝐶N𝐵N ) ) → ( 𝐶 +N 𝐵 ) = ( 𝐶 +o 𝐵 ) )
20 17 19 eleq12d ( ( ( 𝐶N𝐴N ) ∧ ( 𝐶N𝐵N ) ) → ( ( 𝐶 +N 𝐴 ) ∈ ( 𝐶 +N 𝐵 ) ↔ ( 𝐶 +o 𝐴 ) ∈ ( 𝐶 +o 𝐵 ) ) )
21 15 20 bitrd ( ( ( 𝐶N𝐴N ) ∧ ( 𝐶N𝐵N ) ) → ( ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ↔ ( 𝐶 +o 𝐴 ) ∈ ( 𝐶 +o 𝐵 ) ) )
22 21 anandis ( ( 𝐶N ∧ ( 𝐴N𝐵N ) ) → ( ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ↔ ( 𝐶 +o 𝐴 ) ∈ ( 𝐶 +o 𝐵 ) ) )
23 22 ancoms ( ( ( 𝐴N𝐵N ) ∧ 𝐶N ) → ( ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ↔ ( 𝐶 +o 𝐴 ) ∈ ( 𝐶 +o 𝐵 ) ) )
24 9 11 23 3bitr4d ( ( ( 𝐴N𝐵N ) ∧ 𝐶N ) → ( 𝐴 <N 𝐵 ↔ ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ) )
25 24 3impa ( ( 𝐴N𝐵N𝐶N ) → ( 𝐴 <N 𝐵 ↔ ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ) )
26 1 2 3 25 ndmovord ( 𝐶N → ( 𝐴 <N 𝐵 ↔ ( 𝐶 +N 𝐴 ) <N ( 𝐶 +N 𝐵 ) ) )