Theorem resabs1 5883

Description: Absorption law for restriction. Exercise 17 of [TakeutiZaring] p. 25. (Contributed by NM, 9-Aug-1994.)

Assertion

Ref	Expression
resabs1	⊢ (𝐵 ⊆ 𝐶 → ((𝐴 ↾ 𝐶) ↾ 𝐵) = (𝐴 ↾ 𝐵))

Proof of Theorem resabs1

Step	Hyp	Ref	Expression
1		resres 5866	. 2 ⊢ ((𝐴 ↾ 𝐶) ↾ 𝐵) = (𝐴 ↾ (𝐶 ∩ 𝐵))
2		sseqin2 4192	. . 3 ⊢ (𝐵 ⊆ 𝐶 ↔ (𝐶 ∩ 𝐵) = 𝐵)
3		reseq2 5848	. . 3 ⊢ ((𝐶 ∩ 𝐵) = 𝐵 → (𝐴 ↾ (𝐶 ∩ 𝐵)) = (𝐴 ↾ 𝐵))
4	2, 3	sylbi 219	. 2 ⊢ (𝐵 ⊆ 𝐶 → (𝐴 ↾ (𝐶 ∩ 𝐵)) = (𝐴 ↾ 𝐵))
5	1, 4	syl5eq 2868	1 ⊢ (𝐵 ⊆ 𝐶 → ((𝐴 ↾ 𝐶) ↾ 𝐵) = (𝐴 ↾ 𝐵))

Syntax hints:   → wi 4   = wceq 1537   ∩ cin 3935   ⊆ wss 3936   ↾ cres 5557

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2116  ax-9 2124  ax-10 2145  ax-11 2161  ax-12 2177  ax-ext 2793  ax-sep 5203  ax-nul 5210  ax-pr 5330

This theorem depends on definitions:  df-bi 209  df-an 399  df-or 844  df-3an 1085  df-tru 1540  df-ex 1781  df-nf 1785  df-sb 2070  df-clab 2800  df-cleq 2814  df-clel 2893  df-nfc 2963  df-rab 3147  df-v 3496  df-dif 3939  df-un 3941  df-in 3943  df-ss 3952  df-nul 4292  df-if 4468  df-sn 4568  df-pr 4570  df-op 4574  df-opab 5129  df-xp 5561  df-rel 5562  df-res 5567

This theorem is referenced by:  resabs1d  5884  resabs2  5885  resiima  5944  fun2ssres  6399  fssres2  6546  smores3  7990  setsres  16525  gsum2dlem2  19091  lindsss  20968  resthauslem  21971  ptcmpfi  22421  tsmsres  22752  ressxms  23135  nrginvrcn  23301  xrge0gsumle  23441  lebnumii  23570  dfrelog  25149  relogf1o  25150  dvlog  25234  dvlog2  25236  efopnlem2  25240  wilthlem2  25646  gsumle  30725  rrhre  31262  iwrdsplit  31645  rpsqrtcn  31864  pthhashvtx  32374  cvmsss2  32521  nosupres  33207  nosupbnd2lem1  33215  mbfposadd  34954  mzpcompact2lem  39368  eldioph2  39379  diophin  39389  diophrex  39392  2rexfrabdioph  39413  3rexfrabdioph  39414  4rexfrabdioph  39415  6rexfrabdioph  39416  7rexfrabdioph  39417  resabs1i  41434  dvmptresicc  42224  fourierdlem46  42457  fourierdlem57  42468  fourierdlem111  42522  fouriersw  42536  psmeasurelem  42772