Metamath Proof Explorer


Theorem oneo

Description: If an ordinal number is even, its successor is odd. (Contributed by NM, 26-Jan-2006)

Ref Expression
Assertion oneo A On B On C = 2 𝑜 𝑜 A ¬ suc C = 2 𝑜 𝑜 B

Proof

Step Hyp Ref Expression
1 onnbtwn A On ¬ A B B suc A
2 1 3ad2ant1 A On B On C = 2 𝑜 𝑜 A ¬ A B B suc A
3 suceq C = 2 𝑜 𝑜 A suc C = suc 2 𝑜 𝑜 A
4 3 eqeq1d C = 2 𝑜 𝑜 A suc C = 2 𝑜 𝑜 B suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B
5 4 3ad2ant3 A On B On C = 2 𝑜 𝑜 A suc C = 2 𝑜 𝑜 B suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B
6 ovex 2 𝑜 𝑜 A V
7 6 sucid 2 𝑜 𝑜 A suc 2 𝑜 𝑜 A
8 eleq2 suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B 2 𝑜 𝑜 A suc 2 𝑜 𝑜 A 2 𝑜 𝑜 A 2 𝑜 𝑜 B
9 7 8 mpbii suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B 2 𝑜 𝑜 A 2 𝑜 𝑜 B
10 2on 2 𝑜 On
11 omord A On B On 2 𝑜 On A B 2 𝑜 2 𝑜 𝑜 A 2 𝑜 𝑜 B
12 10 11 mp3an3 A On B On A B 2 𝑜 2 𝑜 𝑜 A 2 𝑜 𝑜 B
13 simpl A B 2 𝑜 A B
14 12 13 syl6bir A On B On 2 𝑜 𝑜 A 2 𝑜 𝑜 B A B
15 9 14 syl5 A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B A B
16 simpr A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B
17 omcl 2 𝑜 On A On 2 𝑜 𝑜 A On
18 10 17 mpan A On 2 𝑜 𝑜 A On
19 oa1suc 2 𝑜 𝑜 A On 2 𝑜 𝑜 A + 𝑜 1 𝑜 = suc 2 𝑜 𝑜 A
20 18 19 syl A On 2 𝑜 𝑜 A + 𝑜 1 𝑜 = suc 2 𝑜 𝑜 A
21 1oex 1 𝑜 V
22 21 sucid 1 𝑜 suc 1 𝑜
23 df-2o 2 𝑜 = suc 1 𝑜
24 22 23 eleqtrri 1 𝑜 2 𝑜
25 1on 1 𝑜 On
26 oaord 1 𝑜 On 2 𝑜 On 2 𝑜 𝑜 A On 1 𝑜 2 𝑜 2 𝑜 𝑜 A + 𝑜 1 𝑜 2 𝑜 𝑜 A + 𝑜 2 𝑜
27 25 10 18 26 mp3an12i A On 1 𝑜 2 𝑜 2 𝑜 𝑜 A + 𝑜 1 𝑜 2 𝑜 𝑜 A + 𝑜 2 𝑜
28 24 27 mpbii A On 2 𝑜 𝑜 A + 𝑜 1 𝑜 2 𝑜 𝑜 A + 𝑜 2 𝑜
29 omsuc 2 𝑜 On A On 2 𝑜 𝑜 suc A = 2 𝑜 𝑜 A + 𝑜 2 𝑜
30 10 29 mpan A On 2 𝑜 𝑜 suc A = 2 𝑜 𝑜 A + 𝑜 2 𝑜
31 28 30 eleqtrrd A On 2 𝑜 𝑜 A + 𝑜 1 𝑜 2 𝑜 𝑜 suc A
32 20 31 eqeltrrd A On suc 2 𝑜 𝑜 A 2 𝑜 𝑜 suc A
33 32 ad2antrr A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B suc 2 𝑜 𝑜 A 2 𝑜 𝑜 suc A
34 16 33 eqeltrrd A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B 2 𝑜 𝑜 B 2 𝑜 𝑜 suc A
35 suceloni A On suc A On
36 omord B On suc A On 2 𝑜 On B suc A 2 𝑜 2 𝑜 𝑜 B 2 𝑜 𝑜 suc A
37 10 36 mp3an3 B On suc A On B suc A 2 𝑜 2 𝑜 𝑜 B 2 𝑜 𝑜 suc A
38 35 37 sylan2 B On A On B suc A 2 𝑜 2 𝑜 𝑜 B 2 𝑜 𝑜 suc A
39 38 ancoms A On B On B suc A 2 𝑜 2 𝑜 𝑜 B 2 𝑜 𝑜 suc A
40 39 adantr A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B B suc A 2 𝑜 2 𝑜 𝑜 B 2 𝑜 𝑜 suc A
41 34 40 mpbird A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B B suc A 2 𝑜
42 41 simpld A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B B suc A
43 42 ex A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B B suc A
44 15 43 jcad A On B On suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B A B B suc A
45 44 3adant3 A On B On C = 2 𝑜 𝑜 A suc 2 𝑜 𝑜 A = 2 𝑜 𝑜 B A B B suc A
46 5 45 sylbid A On B On C = 2 𝑜 𝑜 A suc C = 2 𝑜 𝑜 B A B B suc A
47 2 46 mtod A On B On C = 2 𝑜 𝑜 A ¬ suc C = 2 𝑜 𝑜 B