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Mirrors > Home > MPE Home > Th. List > sylan9ss | Structured version Visualization version GIF version |
Description: A subclass transitivity deduction. (Contributed by NM, 27-Sep-2004.) (Proof shortened by Andrew Salmon, 14-Jun-2011.) |
Ref | Expression |
---|---|
sylan9ss.1 | ⊢ (𝜑 → 𝐴 ⊆ 𝐵) |
sylan9ss.2 | ⊢ (𝜓 → 𝐵 ⊆ 𝐶) |
Ref | Expression |
---|---|
sylan9ss | ⊢ ((𝜑 ∧ 𝜓) → 𝐴 ⊆ 𝐶) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sylan9ss.1 | . 2 ⊢ (𝜑 → 𝐴 ⊆ 𝐵) | |
2 | sylan9ss.2 | . 2 ⊢ (𝜓 → 𝐵 ⊆ 𝐶) | |
3 | sstr 3895 | . 2 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐵 ⊆ 𝐶) → 𝐴 ⊆ 𝐶) | |
4 | 1, 2, 3 | syl2an 599 | 1 ⊢ ((𝜑 ∧ 𝜓) → 𝐴 ⊆ 𝐶) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 399 ⊆ wss 3853 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1802 ax-4 1816 ax-5 1917 ax-6 1975 ax-7 2020 ax-8 2116 ax-9 2124 ax-ext 2711 |
This theorem depends on definitions: df-bi 210 df-an 400 df-tru 1545 df-ex 1787 df-sb 2075 df-clab 2718 df-cleq 2731 df-clel 2812 df-v 3402 df-in 3860 df-ss 3870 |
This theorem is referenced by: sylan9ssr 3901 psstr 4005 unss12 4082 ss2in 4137 ssdisj 4359 relrelss 6115 funssxp 6544 axdc3lem 9963 tskuni 10296 rtrclreclem4 14523 tsmsxp 22919 shslubi 29333 chlej12i 29423 insiga 31688 fnetr 34196 pcl0bN 37593 brtrclfv2 40922 |
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