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Mirrors > Home > MPE Home > Th. List > predidm | Structured version Visualization version GIF version |
Description: Idempotent law for the predecessor class. (Contributed by Scott Fenton, 29-Mar-2011.) |
Ref | Expression |
---|---|
predidm | ⊢ Pred(𝑅, Pred(𝑅, 𝐴, 𝑋), 𝑋) = Pred(𝑅, 𝐴, 𝑋) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-pred 6129 | . 2 ⊢ Pred(𝑅, Pred(𝑅, 𝐴, 𝑋), 𝑋) = (Pred(𝑅, 𝐴, 𝑋) ∩ (◡𝑅 “ {𝑋})) | |
2 | df-pred 6129 | . . . . 5 ⊢ Pred(𝑅, 𝐴, 𝑋) = (𝐴 ∩ (◡𝑅 “ {𝑋})) | |
3 | inidm 4109 | . . . . . 6 ⊢ ((◡𝑅 “ {𝑋}) ∩ (◡𝑅 “ {𝑋})) = (◡𝑅 “ {𝑋}) | |
4 | 3 | ineq2i 4100 | . . . . 5 ⊢ (𝐴 ∩ ((◡𝑅 “ {𝑋}) ∩ (◡𝑅 “ {𝑋}))) = (𝐴 ∩ (◡𝑅 “ {𝑋})) |
5 | 2, 4 | eqtr4i 2764 | . . . 4 ⊢ Pred(𝑅, 𝐴, 𝑋) = (𝐴 ∩ ((◡𝑅 “ {𝑋}) ∩ (◡𝑅 “ {𝑋}))) |
6 | inass 4110 | . . . 4 ⊢ ((𝐴 ∩ (◡𝑅 “ {𝑋})) ∩ (◡𝑅 “ {𝑋})) = (𝐴 ∩ ((◡𝑅 “ {𝑋}) ∩ (◡𝑅 “ {𝑋}))) | |
7 | 5, 6 | eqtr4i 2764 | . . 3 ⊢ Pred(𝑅, 𝐴, 𝑋) = ((𝐴 ∩ (◡𝑅 “ {𝑋})) ∩ (◡𝑅 “ {𝑋})) |
8 | 2 | ineq1i 4099 | . . 3 ⊢ (Pred(𝑅, 𝐴, 𝑋) ∩ (◡𝑅 “ {𝑋})) = ((𝐴 ∩ (◡𝑅 “ {𝑋})) ∩ (◡𝑅 “ {𝑋})) |
9 | 7, 8 | eqtr4i 2764 | . 2 ⊢ Pred(𝑅, 𝐴, 𝑋) = (Pred(𝑅, 𝐴, 𝑋) ∩ (◡𝑅 “ {𝑋})) |
10 | 1, 9 | eqtr4i 2764 | 1 ⊢ Pred(𝑅, Pred(𝑅, 𝐴, 𝑋), 𝑋) = Pred(𝑅, 𝐴, 𝑋) |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1542 ∩ cin 3842 {csn 4516 ◡ccnv 5524 “ cima 5528 Predcpred 6128 |
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 2710 |
This theorem depends on definitions: df-bi 210 df-an 400 df-tru 1545 df-ex 1787 df-sb 2075 df-clab 2717 df-cleq 2730 df-clel 2811 df-rab 3062 df-v 3400 df-in 3850 df-pred 6129 |
This theorem is referenced by: (None) |
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