Theorem resf1ext2b 7935

Description: Extension of an injection which is a restriction of a function. (Contributed by AV, 3-Oct-2025.)

Assertion

Ref	Expression
resf1ext2b	⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → ((Fun ◡(𝐹 ↾ 𝐶) ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶)) ↔ Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋}))))

Proof of Theorem resf1ext2b

Step	Hyp	Ref	Expression
1		fssres 6745	. . . . 5 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝐶 ⊆ 𝐴) → (𝐹 ↾ 𝐶):𝐶⟶𝐵)
2	1	3adant2 1149	. . . 4 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (𝐹 ↾ 𝐶):𝐶⟶𝐵)
3		df-f1 6542	. . . . 5 ⊢ ((𝐹 ↾ 𝐶):𝐶–1-1→𝐵 ↔ ((𝐹 ↾ 𝐶):𝐶⟶𝐵 ∧ Fun ◡(𝐹 ↾ 𝐶)))
4		resf1extb 7934	. . . . . . 7 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (((𝐹 ↾ 𝐶):𝐶–1-1→𝐵 ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶)) ↔ (𝐹 ↾ (𝐶 ∪ {𝑋})):(𝐶 ∪ {𝑋})–1-1→𝐵))
5		df-f1 6542	. . . . . . . 8 ⊢ ((𝐹 ↾ (𝐶 ∪ {𝑋})):(𝐶 ∪ {𝑋})–1-1→𝐵 ↔ ((𝐹 ↾ (𝐶 ∪ {𝑋})):(𝐶 ∪ {𝑋})⟶𝐵 ∧ Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋}))))
6	5	simprbi 503	. . . . . . 7 ⊢ ((𝐹 ↾ (𝐶 ∪ {𝑋})):(𝐶 ∪ {𝑋})–1-1→𝐵 → Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋})))
7	4, 6	biimtrdi 256	. . . . . 6 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (((𝐹 ↾ 𝐶):𝐶–1-1→𝐵 ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶)) → Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋}))))
8	7	expd 421	. . . . 5 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → ((𝐹 ↾ 𝐶):𝐶–1-1→𝐵 → ((𝐹‘𝑋) ∉ (𝐹 “ 𝐶) → Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋})))))
9	3, 8	biimtrrid 246	. . . 4 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (((𝐹 ↾ 𝐶):𝐶⟶𝐵 ∧ Fun ◡(𝐹 ↾ 𝐶)) → ((𝐹‘𝑋) ∉ (𝐹 “ 𝐶) → Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋})))))
10	2, 9	mpand 708	. . 3 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (Fun ◡(𝐹 ↾ 𝐶) → ((𝐹‘𝑋) ∉ (𝐹 “ 𝐶) → Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋})))))
11	10	impd 416	. 2 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → ((Fun ◡(𝐹 ↾ 𝐶) ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶)) → Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋}))))
12		simp1 1154	. . . 4 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → 𝐹:𝐴⟶𝐵)
13		simp3 1156	. . . . 5 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → 𝐶 ⊆ 𝐴)
14		eldifi 4081	. . . . . . 7 ⊢ (𝑋 ∈ (𝐴 ∖ 𝐶) → 𝑋 ∈ 𝐴)
15	14	snssd 4750	. . . . . 6 ⊢ (𝑋 ∈ (𝐴 ∖ 𝐶) → {𝑋} ⊆ 𝐴)
16	15	3ad2ant2 1152	. . . . 5 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → {𝑋} ⊆ 𝐴)
17	13, 16	unssd 4141	. . . 4 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (𝐶 ∪ {𝑋}) ⊆ 𝐴)
18	12, 17	fssresd 6746	. . 3 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (𝐹 ↾ (𝐶 ∪ {𝑋})):(𝐶 ∪ {𝑋})⟶𝐵)
19	3	simprbi 503	. . . . . 6 ⊢ ((𝐹 ↾ 𝐶):𝐶–1-1→𝐵 → Fun ◡(𝐹 ↾ 𝐶))
20	19	anim1i 627	. . . . 5 ⊢ (((𝐹 ↾ 𝐶):𝐶–1-1→𝐵 ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶)) → (Fun ◡(𝐹 ↾ 𝐶) ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶)))
21	4, 20	biimtrrdi 257	. . . 4 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → ((𝐹 ↾ (𝐶 ∪ {𝑋})):(𝐶 ∪ {𝑋})–1-1→𝐵 → (Fun ◡(𝐹 ↾ 𝐶) ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶))))
22	5, 21	biimtrrid 246	. . 3 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (((𝐹 ↾ (𝐶 ∪ {𝑋})):(𝐶 ∪ {𝑋})⟶𝐵 ∧ Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋}))) → (Fun ◡(𝐹 ↾ 𝐶) ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶))))
23	18, 22	mpand 708	. 2 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → (Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋})) → (Fun ◡(𝐹 ↾ 𝐶) ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶))))
24	11, 23	impbid 215	1 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝑋 ∈ (𝐴 ∖ 𝐶) ∧ 𝐶 ⊆ 𝐴) → ((Fun ◡(𝐹 ↾ 𝐶) ∧ (𝐹‘𝑋) ∉ (𝐹 “ 𝐶)) ↔ Fun ◡(𝐹 ↾ (𝐶 ∪ {𝑋}))))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   ∧ w3a 1103   ∈ wcel 2145   ∉ wnel 3063   ∖ cdif 3899   ∪ cun 3900   ⊆ wss 3902  {csn 4587  ^◡ccnv 5658   ↾ cres 5661   “ cima 5662  Fun wfun 6531  ⟶wf 6533  –1-1→wf1 6534  ‘cfv 6537

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 2215  ax-ext 2734  ax-sep 5255  ax-nul 5267  ax-pr 5402

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2566  df-eu 2596  df-clab 2741  df-cleq 2754  df-clel 2837  df-ne 2958  df-nel 3064  df-ral 3079  df-rex 3089  df-rab 3415  df-v 3455  df-dif 3905  df-un 3907  df-in 3909  df-ss 3919  df-nul 4283  df-if 4486  df-sn 4588  df-pr 4590  df-op 4594  df-uni 4871  df-br 5108  df-opab 5172  df-id 5554  df-xp 5665  df-rel 5666  df-cnv 5667  df-co 5668  df-dm 5669  df-rn 5670  df-res 5671  df-ima 5672  df-iota 6493  df-fun 6539  df-fn 6540  df-f 6541  df-f1 6542  df-fv 6545

This theorem is used by:  dfpth2  30179