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Mirrors > Home > MPE Home > Th. List > lfgrnloop | Structured version Visualization version GIF version |
Description: A loop-free graph has no loops. (Contributed by AV, 23-Feb-2021.) |
Ref | Expression |
---|---|
lfuhgrnloopv.i | ⊢ 𝐼 = (iEdg‘𝐺) |
lfuhgrnloopv.a | ⊢ 𝐴 = dom 𝐼 |
lfuhgrnloopv.e | ⊢ 𝐸 = {𝑥 ∈ 𝒫 𝑉 ∣ 2 ≤ (#‘𝑥)} |
Ref | Expression |
---|---|
lfgrnloop | ⊢ (𝐼:𝐴⟶𝐸 → {𝑥 ∈ 𝐴 ∣ (𝐼‘𝑥) = {𝑈}} = ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nfcv 2751 | . . . 4 ⊢ Ⅎ𝑥𝐼 | |
2 | nfcv 2751 | . . . 4 ⊢ Ⅎ𝑥𝐴 | |
3 | lfuhgrnloopv.e | . . . . 5 ⊢ 𝐸 = {𝑥 ∈ 𝒫 𝑉 ∣ 2 ≤ (#‘𝑥)} | |
4 | nfrab1 3099 | . . . . 5 ⊢ Ⅎ𝑥{𝑥 ∈ 𝒫 𝑉 ∣ 2 ≤ (#‘𝑥)} | |
5 | 3, 4 | nfcxfr 2749 | . . . 4 ⊢ Ⅎ𝑥𝐸 |
6 | 1, 2, 5 | nff 5954 | . . 3 ⊢ Ⅎ𝑥 𝐼:𝐴⟶𝐸 |
7 | hashsn01 13065 | . . . . . . 7 ⊢ ((#‘{𝑈}) = 0 ∨ (#‘{𝑈}) = 1) | |
8 | 2pos 10989 | . . . . . . . . . 10 ⊢ 0 < 2 | |
9 | 0re 9919 | . . . . . . . . . . 11 ⊢ 0 ∈ ℝ | |
10 | 2re 10967 | . . . . . . . . . . 11 ⊢ 2 ∈ ℝ | |
11 | 9, 10 | ltnlei 10037 | . . . . . . . . . 10 ⊢ (0 < 2 ↔ ¬ 2 ≤ 0) |
12 | 8, 11 | mpbi 219 | . . . . . . . . 9 ⊢ ¬ 2 ≤ 0 |
13 | breq2 4587 | . . . . . . . . 9 ⊢ ((#‘{𝑈}) = 0 → (2 ≤ (#‘{𝑈}) ↔ 2 ≤ 0)) | |
14 | 12, 13 | mtbiri 316 | . . . . . . . 8 ⊢ ((#‘{𝑈}) = 0 → ¬ 2 ≤ (#‘{𝑈})) |
15 | 1lt2 11071 | . . . . . . . . . 10 ⊢ 1 < 2 | |
16 | 1re 9918 | . . . . . . . . . . 11 ⊢ 1 ∈ ℝ | |
17 | 16, 10 | ltnlei 10037 | . . . . . . . . . 10 ⊢ (1 < 2 ↔ ¬ 2 ≤ 1) |
18 | 15, 17 | mpbi 219 | . . . . . . . . 9 ⊢ ¬ 2 ≤ 1 |
19 | breq2 4587 | . . . . . . . . 9 ⊢ ((#‘{𝑈}) = 1 → (2 ≤ (#‘{𝑈}) ↔ 2 ≤ 1)) | |
20 | 18, 19 | mtbiri 316 | . . . . . . . 8 ⊢ ((#‘{𝑈}) = 1 → ¬ 2 ≤ (#‘{𝑈})) |
21 | 14, 20 | jaoi 393 | . . . . . . 7 ⊢ (((#‘{𝑈}) = 0 ∨ (#‘{𝑈}) = 1) → ¬ 2 ≤ (#‘{𝑈})) |
22 | 7, 21 | ax-mp 5 | . . . . . 6 ⊢ ¬ 2 ≤ (#‘{𝑈}) |
23 | fveq2 6103 | . . . . . . 7 ⊢ ((𝐼‘𝑥) = {𝑈} → (#‘(𝐼‘𝑥)) = (#‘{𝑈})) | |
24 | 23 | breq2d 4595 | . . . . . 6 ⊢ ((𝐼‘𝑥) = {𝑈} → (2 ≤ (#‘(𝐼‘𝑥)) ↔ 2 ≤ (#‘{𝑈}))) |
25 | 22, 24 | mtbiri 316 | . . . . 5 ⊢ ((𝐼‘𝑥) = {𝑈} → ¬ 2 ≤ (#‘(𝐼‘𝑥))) |
26 | lfuhgrnloopv.i | . . . . . 6 ⊢ 𝐼 = (iEdg‘𝐺) | |
27 | lfuhgrnloopv.a | . . . . . 6 ⊢ 𝐴 = dom 𝐼 | |
28 | 26, 27, 3 | lfgredgge2 25790 | . . . . 5 ⊢ ((𝐼:𝐴⟶𝐸 ∧ 𝑥 ∈ 𝐴) → 2 ≤ (#‘(𝐼‘𝑥))) |
29 | 25, 28 | nsyl3 132 | . . . 4 ⊢ ((𝐼:𝐴⟶𝐸 ∧ 𝑥 ∈ 𝐴) → ¬ (𝐼‘𝑥) = {𝑈}) |
30 | 29 | ex 449 | . . 3 ⊢ (𝐼:𝐴⟶𝐸 → (𝑥 ∈ 𝐴 → ¬ (𝐼‘𝑥) = {𝑈})) |
31 | 6, 30 | ralrimi 2940 | . 2 ⊢ (𝐼:𝐴⟶𝐸 → ∀𝑥 ∈ 𝐴 ¬ (𝐼‘𝑥) = {𝑈}) |
32 | rabeq0 3911 | . 2 ⊢ ({𝑥 ∈ 𝐴 ∣ (𝐼‘𝑥) = {𝑈}} = ∅ ↔ ∀𝑥 ∈ 𝐴 ¬ (𝐼‘𝑥) = {𝑈}) | |
33 | 31, 32 | sylibr 223 | 1 ⊢ (𝐼:𝐴⟶𝐸 → {𝑥 ∈ 𝐴 ∣ (𝐼‘𝑥) = {𝑈}} = ∅) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∨ wo 382 ∧ wa 383 = wceq 1475 ∈ wcel 1977 ∀wral 2896 {crab 2900 ∅c0 3874 𝒫 cpw 4108 {csn 4125 class class class wbr 4583 dom cdm 5038 ⟶wf 5800 ‘cfv 5804 0cc0 9815 1c1 9816 < clt 9953 ≤ cle 9954 2c2 10947 #chash 12979 iEdgciedg 25674 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 ax-6 1875 ax-7 1922 ax-8 1979 ax-9 1986 ax-10 2006 ax-11 2021 ax-12 2034 ax-13 2234 ax-ext 2590 ax-sep 4709 ax-nul 4717 ax-pow 4769 ax-pr 4833 ax-un 6847 ax-cnex 9871 ax-resscn 9872 ax-1cn 9873 ax-icn 9874 ax-addcl 9875 ax-addrcl 9876 ax-mulcl 9877 ax-mulrcl 9878 ax-mulcom 9879 ax-addass 9880 ax-mulass 9881 ax-distr 9882 ax-i2m1 9883 ax-1ne0 9884 ax-1rid 9885 ax-rnegex 9886 ax-rrecex 9887 ax-cnre 9888 ax-pre-lttri 9889 ax-pre-lttrn 9890 ax-pre-ltadd 9891 ax-pre-mulgt0 9892 |
This theorem depends on definitions: df-bi 196 df-or 384 df-an 385 df-3or 1032 df-3an 1033 df-tru 1478 df-ex 1696 df-nf 1701 df-sb 1868 df-eu 2462 df-mo 2463 df-clab 2597 df-cleq 2603 df-clel 2606 df-nfc 2740 df-ne 2782 df-nel 2783 df-ral 2901 df-rex 2902 df-reu 2903 df-rab 2905 df-v 3175 df-sbc 3403 df-csb 3500 df-dif 3543 df-un 3545 df-in 3547 df-ss 3554 df-pss 3556 df-nul 3875 df-if 4037 df-pw 4110 df-sn 4126 df-pr 4128 df-tp 4130 df-op 4132 df-uni 4373 df-int 4411 df-iun 4457 df-br 4584 df-opab 4644 df-mpt 4645 df-tr 4681 df-eprel 4949 df-id 4953 df-po 4959 df-so 4960 df-fr 4997 df-we 4999 df-xp 5044 df-rel 5045 df-cnv 5046 df-co 5047 df-dm 5048 df-rn 5049 df-res 5050 df-ima 5051 df-pred 5597 df-ord 5643 df-on 5644 df-lim 5645 df-suc 5646 df-iota 5768 df-fun 5806 df-fn 5807 df-f 5808 df-f1 5809 df-fo 5810 df-f1o 5811 df-fv 5812 df-riota 6511 df-ov 6552 df-oprab 6553 df-mpt2 6554 df-om 6958 df-1st 7059 df-2nd 7060 df-wrecs 7294 df-recs 7355 df-rdg 7393 df-1o 7447 df-er 7629 df-en 7842 df-dom 7843 df-sdom 7844 df-fin 7845 df-card 8648 df-pnf 9955 df-mnf 9956 df-xr 9957 df-ltxr 9958 df-le 9959 df-sub 10147 df-neg 10148 df-nn 10898 df-2 10956 df-n0 11170 df-z 11255 df-uz 11564 df-fz 12198 df-hash 12980 |
This theorem is referenced by: vtxdlfgrval 40700 |
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