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Mirrors > Home > NFE Home > Th. List > funsn | GIF version |
Description: A singleton of an ordered pair is a function. Theorem 10.5 of [Quine] p. 65. (Contributed by NM, 12-Aug-1994.) (Revised by Scott Fenton, 16-Apr-2021.) |
Ref | Expression |
---|---|
funsn | ⊢ Fun {〈A, B〉} |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dffun6 5124 | . 2 ⊢ (Fun {〈A, B〉} ↔ ∀x∃*y x{〈A, B〉}y) | |
2 | moeq 3012 | . . . 4 ⊢ ∃*y y = B | |
3 | 2 | a1i 10 | . . 3 ⊢ (x = A → ∃*y y = B) |
4 | df-br 4640 | . . . . . 6 ⊢ (x{〈A, B〉}y ↔ 〈x, y〉 ∈ {〈A, B〉}) | |
5 | vex 2862 | . . . . . . . . 9 ⊢ x ∈ V | |
6 | vex 2862 | . . . . . . . . 9 ⊢ y ∈ V | |
7 | 5, 6 | opex 4588 | . . . . . . . 8 ⊢ 〈x, y〉 ∈ V |
8 | 7 | elsnc 3756 | . . . . . . 7 ⊢ (〈x, y〉 ∈ {〈A, B〉} ↔ 〈x, y〉 = 〈A, B〉) |
9 | opth 4602 | . . . . . . 7 ⊢ (〈x, y〉 = 〈A, B〉 ↔ (x = A ∧ y = B)) | |
10 | 8, 9 | bitri 240 | . . . . . 6 ⊢ (〈x, y〉 ∈ {〈A, B〉} ↔ (x = A ∧ y = B)) |
11 | 4, 10 | bitri 240 | . . . . 5 ⊢ (x{〈A, B〉}y ↔ (x = A ∧ y = B)) |
12 | 11 | mobii 2240 | . . . 4 ⊢ (∃*y x{〈A, B〉}y ↔ ∃*y(x = A ∧ y = B)) |
13 | moanimv 2262 | . . . 4 ⊢ (∃*y(x = A ∧ y = B) ↔ (x = A → ∃*y y = B)) | |
14 | 12, 13 | bitri 240 | . . 3 ⊢ (∃*y x{〈A, B〉}y ↔ (x = A → ∃*y y = B)) |
15 | 3, 14 | mpbir 200 | . 2 ⊢ ∃*y x{〈A, B〉}y |
16 | 1, 15 | mpgbir 1550 | 1 ⊢ Fun {〈A, B〉} |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 358 = wceq 1642 ∈ wcel 1710 ∃*wmo 2205 {csn 3737 〈cop 4561 class class class wbr 4639 Fun wfun 4775 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1546 ax-5 1557 ax-17 1616 ax-9 1654 ax-8 1675 ax-13 1712 ax-14 1714 ax-6 1729 ax-7 1734 ax-11 1746 ax-12 1925 ax-ext 2334 ax-nin 4078 ax-xp 4079 ax-cnv 4080 ax-1c 4081 ax-sset 4082 ax-si 4083 ax-ins2 4084 ax-ins3 4085 ax-typlower 4086 ax-sn 4087 |
This theorem depends on definitions: df-bi 177 df-or 359 df-an 360 df-3or 935 df-3an 936 df-nan 1288 df-tru 1319 df-ex 1542 df-nf 1545 df-sb 1649 df-eu 2208 df-mo 2209 df-clab 2340 df-cleq 2346 df-clel 2349 df-nfc 2478 df-ne 2518 df-ral 2619 df-rex 2620 df-reu 2621 df-rmo 2622 df-rab 2623 df-v 2861 df-sbc 3047 df-nin 3211 df-compl 3212 df-in 3213 df-un 3214 df-dif 3215 df-symdif 3216 df-ss 3259 df-pss 3261 df-nul 3551 df-if 3663 df-pw 3724 df-sn 3741 df-pr 3742 df-uni 3892 df-int 3927 df-opk 4058 df-1c 4136 df-pw1 4137 df-uni1 4138 df-xpk 4185 df-cnvk 4186 df-ins2k 4187 df-ins3k 4188 df-imak 4189 df-cok 4190 df-p6 4191 df-sik 4192 df-ssetk 4193 df-imagek 4194 df-idk 4195 df-iota 4339 df-0c 4377 df-addc 4378 df-nnc 4379 df-fin 4380 df-lefin 4440 df-ltfin 4441 df-ncfin 4442 df-tfin 4443 df-evenfin 4444 df-oddfin 4445 df-sfin 4446 df-spfin 4447 df-phi 4565 df-op 4566 df-proj1 4567 df-proj2 4568 df-opab 4623 df-br 4640 df-co 4726 df-id 4767 df-cnv 4785 df-fun 4789 |
This theorem is referenced by: funsngOLD 5148 funprg 5149 fnsn 5152 fvsn 5445 |
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