Theorem noreson 33863

Description: The restriction of a surreal to an ordinal is still a surreal. (Contributed by Scott Fenton, 4-Sep-2011.)

Assertion

Ref	Expression
noreson	⊢ ((𝐴 ∈ No ∧ 𝐵 ∈ On) → (𝐴 ↾ 𝐵) ∈ No )

Proof of Theorem noreson

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

Step	Hyp	Ref	Expression
1		elno 33849	. . 3 ⊢ (𝐴 ∈ No ↔ ∃𝑥 ∈ On 𝐴:𝑥⟶{1o, 2o})
2		onin 6297	. . . . . . . 8 ⊢ ((𝑥 ∈ On ∧ 𝐵 ∈ On) → (𝑥 ∩ 𝐵) ∈ On)
3		fresin 6643	. . . . . . . 8 ⊢ (𝐴:𝑥⟶{1o, 2o} → (𝐴 ↾ 𝐵):(𝑥 ∩ 𝐵)⟶{1o, 2o})
4		feq2 6582	. . . . . . . . 9 ⊢ (𝑦 = (𝑥 ∩ 𝐵) → ((𝐴 ↾ 𝐵):𝑦⟶{1o, 2o} ↔ (𝐴 ↾ 𝐵):(𝑥 ∩ 𝐵)⟶{1o, 2o}))
5	4	rspcev 3561	. . . . . . . 8 ⊢ (((𝑥 ∩ 𝐵) ∈ On ∧ (𝐴 ↾ 𝐵):(𝑥 ∩ 𝐵)⟶{1o, 2o}) → ∃𝑦 ∈ On (𝐴 ↾ 𝐵):𝑦⟶{1o, 2o})
6	2, 3, 5	syl2an 596	. . . . . . 7 ⊢ (((𝑥 ∈ On ∧ 𝐵 ∈ On) ∧ 𝐴:𝑥⟶{1o, 2o}) → ∃𝑦 ∈ On (𝐴 ↾ 𝐵):𝑦⟶{1o, 2o})
7	6	an32s 649	. . . . . 6 ⊢ (((𝑥 ∈ On ∧ 𝐴:𝑥⟶{1o, 2o}) ∧ 𝐵 ∈ On) → ∃𝑦 ∈ On (𝐴 ↾ 𝐵):𝑦⟶{1o, 2o})
8	7	ex 413	. . . . 5 ⊢ ((𝑥 ∈ On ∧ 𝐴:𝑥⟶{1o, 2o}) → (𝐵 ∈ On → ∃𝑦 ∈ On (𝐴 ↾ 𝐵):𝑦⟶{1o, 2o}))
9	8	rexlimiva 3210	. . . 4 ⊢ (∃𝑥 ∈ On 𝐴:𝑥⟶{1o, 2o} → (𝐵 ∈ On → ∃𝑦 ∈ On (𝐴 ↾ 𝐵):𝑦⟶{1o, 2o}))
10	9	imp 407	. . 3 ⊢ ((∃𝑥 ∈ On 𝐴:𝑥⟶{1o, 2o} ∧ 𝐵 ∈ On) → ∃𝑦 ∈ On (𝐴 ↾ 𝐵):𝑦⟶{1o, 2o})
11	1, 10	sylanb 581	. 2 ⊢ ((𝐴 ∈ No ∧ 𝐵 ∈ On) → ∃𝑦 ∈ On (𝐴 ↾ 𝐵):𝑦⟶{1o, 2o})
12		elno 33849	. 2 ⊢ ((𝐴 ↾ 𝐵) ∈ No ↔ ∃𝑦 ∈ On (𝐴 ↾ 𝐵):𝑦⟶{1o, 2o})
13	11, 12	sylibr 233	1 ⊢ ((𝐴 ∈ No ∧ 𝐵 ∈ On) → (𝐴 ↾ 𝐵) ∈ No )

Syntax hints:   → wi 4   ∧ wa 396   ∈ wcel 2106  ∃wrex 3065   ∩ cin 3886  {cpr 4563   ↾ cres 5591  Oncon0 6266  ⟶wf 6429  1_oc1o 8290  2_oc2o 8291   No csur 33843

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1913  ax-6 1971  ax-7 2011  ax-8 2108  ax-9 2116  ax-10 2137  ax-11 2154  ax-12 2171  ax-ext 2709  ax-rep 5209  ax-sep 5223  ax-nul 5230  ax-pr 5352

This theorem depends on definitions:  df-bi 206  df-an 397  df-or 845  df-3an 1088  df-tru 1542  df-fal 1552  df-ex 1783  df-nf 1787  df-sb 2068  df-mo 2540  df-eu 2569  df-clab 2716  df-cleq 2730  df-clel 2816  df-nfc 2889  df-ne 2944  df-ral 3069  df-rex 3070  df-reu 3072  df-rab 3073  df-v 3434  df-sbc 3717  df-csb 3833  df-dif 3890  df-un 3892  df-in 3894  df-ss 3904  df-nul 4257  df-if 4460  df-sn 4562  df-pr 4564  df-op 4568  df-uni 4840  df-iun 4926  df-br 5075  df-opab 5137  df-mpt 5158  df-tr 5192  df-id 5489  df-po 5503  df-so 5504  df-fr 5544  df-we 5546  df-xp 5595  df-rel 5596  df-cnv 5597  df-co 5598  df-dm 5599  df-rn 5600  df-res 5601  df-ima 5602  df-ord 6269  df-on 6270  df-iota 6391  df-fun 6435  df-fn 6436  df-f 6437  df-f1 6438  df-fo 6439  df-f1o 6440  df-fv 6441  df-no 33846

This theorem is referenced by:  sltres  33865  nodenselem6  33892  noresle  33900  nosupbnd1lem1  33911  nosupbnd1lem2  33912  nosupbnd1lem6  33916  nosupbnd1  33917  nosupbnd2lem1  33918  nosupbnd2  33919  noinfbnd1lem1  33926  noinfbnd1lem2  33927  noinfbnd1lem6  33931  noinfbnd1  33932  noinfbnd2lem1  33933  noinfbnd2  33934  nosupinfsep  33935  noetasuplem4  33939  noetainflem4  33943