Theorem oldbday 27893

Description: A surreal is part of the set older than ordinal 𝐴 iff its birthday is less than 𝐴. Remark in [Conway] p. 29. (Contributed by Scott Fenton, 19-Aug-2024.)

Assertion

Ref	Expression
oldbday	⊢ ((𝐴 ∈ On ∧ 𝑋 ∈ No ) → (𝑋 ∈ ( O ‘𝐴) ↔ ( bday ‘𝑋) ∈ 𝐴))

Proof of Theorem oldbday

Dummy variables 𝑏 𝑦 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		oldbdayim 27881	. 2 ⊢ (𝑋 ∈ ( O ‘𝐴) → ( bday ‘𝑋) ∈ 𝐴)
2		simpl 482	. . 3 ⊢ ((𝐴 ∈ On ∧ 𝑋 ∈ No ) → 𝐴 ∈ On)
3		onelon 6348	. . . . . . 7 ⊢ ((𝐴 ∈ On ∧ 𝑏 ∈ 𝐴) → 𝑏 ∈ On)
4		madebday 27892	. . . . . . . 8 ⊢ ((𝑏 ∈ On ∧ 𝑦 ∈ No ) → (𝑦 ∈ ( M ‘𝑏) ↔ ( bday ‘𝑦) ⊆ 𝑏))
5	4	biimprd 248	. . . . . . 7 ⊢ ((𝑏 ∈ On ∧ 𝑦 ∈ No ) → (( bday ‘𝑦) ⊆ 𝑏 → 𝑦 ∈ ( M ‘𝑏)))
6	3, 5	sylan 581	. . . . . 6 ⊢ (((𝐴 ∈ On ∧ 𝑏 ∈ 𝐴) ∧ 𝑦 ∈ No ) → (( bday ‘𝑦) ⊆ 𝑏 → 𝑦 ∈ ( M ‘𝑏)))
7	6	anasss 466	. . . . 5 ⊢ ((𝐴 ∈ On ∧ (𝑏 ∈ 𝐴 ∧ 𝑦 ∈ No )) → (( bday ‘𝑦) ⊆ 𝑏 → 𝑦 ∈ ( M ‘𝑏)))
8	7	ralrimivva 3180	. . . 4 ⊢ (𝐴 ∈ On → ∀𝑏 ∈ 𝐴 ∀𝑦 ∈ No (( bday ‘𝑦) ⊆ 𝑏 → 𝑦 ∈ ( M ‘𝑏)))
9	8	adantr 480	. . 3 ⊢ ((𝐴 ∈ On ∧ 𝑋 ∈ No ) → ∀𝑏 ∈ 𝐴 ∀𝑦 ∈ No (( bday ‘𝑦) ⊆ 𝑏 → 𝑦 ∈ ( M ‘𝑏)))
10		simpr 484	. . 3 ⊢ ((𝐴 ∈ On ∧ 𝑋 ∈ No ) → 𝑋 ∈ No )
11		madebdaylemold 27890	. . 3 ⊢ ((𝐴 ∈ On ∧ ∀𝑏 ∈ 𝐴 ∀𝑦 ∈ No (( bday ‘𝑦) ⊆ 𝑏 → 𝑦 ∈ ( M ‘𝑏)) ∧ 𝑋 ∈ No ) → (( bday ‘𝑋) ∈ 𝐴 → 𝑋 ∈ ( O ‘𝐴)))
12	2, 9, 10, 11	syl3anc 1374	. 2 ⊢ ((𝐴 ∈ On ∧ 𝑋 ∈ No ) → (( bday ‘𝑋) ∈ 𝐴 → 𝑋 ∈ ( O ‘𝐴)))
13	1, 12	impbid2 226	1 ⊢ ((𝐴 ∈ On ∧ 𝑋 ∈ No ) → (𝑋 ∈ ( O ‘𝐴) ↔ ( bday ‘𝑋) ∈ 𝐴))

Syntax hints:   → wi 4   ↔ wb 206   ∧ wa 395   ∈ wcel 2114  ∀wral 3051   ⊆ wss 3889  Oncon0 6323  ‘cfv 6498   No csur 27603   bday cbday 27605   M cmade 27814   O cold 27815

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1912  ax-6 1969  ax-7 2010  ax-8 2116  ax-9 2124  ax-10 2147  ax-11 2163  ax-12 2185  ax-ext 2708  ax-rep 5212  ax-sep 5231  ax-nul 5241  ax-pow 5307  ax-pr 5375  ax-un 7689

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-3or 1088  df-3an 1089  df-tru 1545  df-fal 1555  df-ex 1782  df-nf 1786  df-sb 2069  df-mo 2539  df-eu 2569  df-clab 2715  df-cleq 2728  df-clel 2811  df-nfc 2885  df-ne 2933  df-ral 3052  df-rex 3062  df-rmo 3342  df-reu 3343  df-rab 3390  df-v 3431  df-sbc 3729  df-csb 3838  df-dif 3892  df-un 3894  df-in 3896  df-ss 3906  df-pss 3909  df-nul 4274  df-if 4467  df-pw 4543  df-sn 4568  df-pr 4570  df-tp 4572  df-op 4574  df-uni 4851  df-int 4890  df-iun 4935  df-br 5086  df-opab 5148  df-mpt 5167  df-tr 5193  df-id 5526  df-eprel 5531  df-po 5539  df-so 5540  df-fr 5584  df-we 5586  df-xp 5637  df-rel 5638  df-cnv 5639  df-co 5640  df-dm 5641  df-rn 5642  df-res 5643  df-ima 5644  df-pred 6265  df-ord 6326  df-on 6327  df-suc 6329  df-iota 6454  df-fun 6500  df-fn 6501  df-f 6502  df-f1 6503  df-fo 6504  df-f1o 6505  df-fv 6506  df-riota 7324  df-ov 7370  df-oprab 7371  df-mpo 7372  df-2nd 7943  df-frecs 8231  df-wrecs 8262  df-recs 8311  df-1o 8405  df-2o 8406  df-no 27606  df-lts 27607  df-bday 27608  df-slts 27750  df-cuts 27752  df-made 27819  df-old 27820  df-left 27822  df-right 27823

This theorem is referenced by:  newbday  27894  0elold  27902  cofcutr  27916  lrrecval2  27932  addsproplem2  27962  addsproplem4  27964  addsproplem5  27965  addsproplem6  27966  negsproplem4  28023  negsproplem5  28024  negsproplem6  28025  negleft  28050  negright  28051  mulsproplem12  28119  mulsproplem13  28120  mulsproplem14  28121  ltonold  28253  oncutlt  28256  onnolt  28258  onlts  28259  oniso  28263  n0ssoldg  28345  onsfi  28348  bdayfinbndlem1  28459  dfz12s2  28480