Theorem lesrecd 28168

Description: A comparison law for surreals considered as cuts of sets of surreals. Definition from [Conway] p. 4. Theorem 4 of [Alling] p. 186. Theorem 2.5 of [Gonshor] p. 9. (Contributed by Scott Fenton, 5-Dec-2025.)

Hypotheses

Ref	Expression
lesrecd.1	⊢ (𝜑 → 𝐴 <<s 𝐵)
lesrecd.2	⊢ (𝜑 → 𝐶 <<s 𝐷)
lesrecd.3	⊢ (𝜑 → 𝑋 = (𝐴 |s 𝐵))
lesrecd.4	⊢ (𝜑 → 𝑌 = (𝐶 |s 𝐷))

Assertion

Ref	Expression
lesrecd	⊢ (𝜑 → (𝑋 ≤s 𝑌 ↔ (∀𝑑 ∈ 𝐷 𝑋 <s 𝑑 ∧ ∀𝑎 ∈ 𝐴 𝑎 <s 𝑌)))

Distinct variable groups:   𝐴,𝑎,𝑑   𝐵,𝑎,𝑑   𝐶,𝑎,𝑑   𝐷,𝑎,𝑑   𝑋,𝑎,𝑑   𝑌,𝑎,𝑑

Allowed substitution hints:   𝜑(𝑎, 𝑑)

Proof of Theorem lesrecd

Step	Hyp	Ref	Expression
1		lesrecd.1	. 2 ⊢ (𝜑 → 𝐴 <<s 𝐵)
2		lesrecd.2	. 2 ⊢ (𝜑 → 𝐶 <<s 𝐷)
3		lesrecd.3	. 2 ⊢ (𝜑 → 𝑋 = (𝐴 |s 𝐵))
4		lesrecd.4	. 2 ⊢ (𝜑 → 𝑌 = (𝐶 |s 𝐷))
5		lesrec 28167	. 2 ⊢ (((𝐴 <<s 𝐵 ∧ 𝐶 <<s 𝐷) ∧ (𝑋 = (𝐴 |s 𝐵) ∧ 𝑌 = (𝐶 |s 𝐷))) → (𝑋 ≤s 𝑌 ↔ (∀𝑑 ∈ 𝐷 𝑋 <s 𝑑 ∧ ∀𝑎 ∈ 𝐴 𝑎 <s 𝑌)))
6	1, 2, 3, 4, 5	syl22anc 852	1 ⊢ (𝜑 → (𝑋 ≤s 𝑌 ↔ (∀𝑑 ∈ 𝐷 𝑋 <s 𝑑 ∧ ∀𝑎 ∈ 𝐴 𝑎 <s 𝑌)))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   = wceq 1570  ∀wral 3077   class class class wbr 5103  (class class class)co 7412   <s clts 27980   ≤s cles 28083   <<s cslts 28125   |s ccuts 28127

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-10 2178  ax-11 2194  ax-12 2213  ax-ext 2733  ax-rep 5232  ax-sep 5249  ax-nul 5260  ax-pow 5327  ax-pr 5391  ax-un 7740

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3or 1104  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2565  df-eu 2595  df-clab 2740  df-cleq 2753  df-clel 2836  df-nfc 2910  df-ne 2957  df-ral 3078  df-rex 3088  df-rmo 3366  df-reu 3367  df-rab 3414  df-v 3453  df-sbc 3740  df-csb 3848  df-dif 3902  df-un 3904  df-in 3906  df-ss 3916  df-pss 3919  df-nul 4280  df-if 4483  df-pw 4559  df-sn 4585  df-pr 4587  df-tp 4589  df-op 4591  df-uni 4868  df-int 4908  df-br 5104  df-opab 5168  df-mpt 5187  df-tr 5213  df-id 5546  df-eprel 5551  df-po 5559  df-so 5560  df-fr 5604  df-we 5606  df-xp 5657  df-rel 5658  df-cnv 5659  df-co 5660  df-dm 5661  df-rn 5662  df-res 5663  df-ima 5664  df-ord 6358  df-on 6359  df-suc 6361  df-iota 6487  df-fun 6533  df-fn 6534  df-f 6535  df-f1 6536  df-fo 6537  df-f1o 6538  df-fv 6539  df-riota 7369  df-ov 7415  df-oprab 7416  df-mpo 7417  df-1o 8460  df-2o 8461  df-no 27982  df-lts 27983  df-bday 27984  df-les 28084  df-slts 28126  df-cuts 28128

This theorem is used by:  ltsrec  28169  eqcuts3  28172  rightge0  28189  onsbnd  28649