Theorem f1ss 6555

Description: A function that is one-to-one is also one-to-one on some superset of its codomain. (Contributed by Mario Carneiro, 12-Jan-2013.)

Assertion

Ref	Expression
f1ss	⊢ ((𝐹:𝐴–1-1→𝐵 ∧ 𝐵 ⊆ 𝐶) → 𝐹:𝐴–1-1→𝐶)

Proof of Theorem f1ss

Step	Hyp	Ref	Expression
1		f1f 6549	. . 3 ⊢ (𝐹:𝐴–1-1→𝐵 → 𝐹:𝐴⟶𝐵)
2		fss 6501	. . 3 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝐵 ⊆ 𝐶) → 𝐹:𝐴⟶𝐶)
3	1, 2	sylan 583	. 2 ⊢ ((𝐹:𝐴–1-1→𝐵 ∧ 𝐵 ⊆ 𝐶) → 𝐹:𝐴⟶𝐶)
4		df-f1 6329	. . . 4 ⊢ (𝐹:𝐴–1-1→𝐵 ↔ (𝐹:𝐴⟶𝐵 ∧ Fun ◡𝐹))
5	4	simprbi 500	. . 3 ⊢ (𝐹:𝐴–1-1→𝐵 → Fun ◡𝐹)
6	5	adantr 484	. 2 ⊢ ((𝐹:𝐴–1-1→𝐵 ∧ 𝐵 ⊆ 𝐶) → Fun ◡𝐹)
7		df-f1 6329	. 2 ⊢ (𝐹:𝐴–1-1→𝐶 ↔ (𝐹:𝐴⟶𝐶 ∧ Fun ◡𝐹))
8	3, 6, 7	sylanbrc 586	1 ⊢ ((𝐹:𝐴–1-1→𝐵 ∧ 𝐵 ⊆ 𝐶) → 𝐹:𝐴–1-1→𝐶)

Syntax hints:   → wi 4   ∧ wa 399   ⊆ wss 3881  ^◡ccnv 5518  Fun wfun 6318  ⟶wf 6320  –1-1→wf1 6321

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-ext 2770

This theorem depends on definitions:  df-bi 210  df-an 400  df-ex 1782  df-sb 2070  df-clab 2777  df-cleq 2791  df-clel 2870  df-v 3443  df-in 3888  df-ss 3898  df-f 6328  df-f1 6329

This theorem is referenced by:  f1sng  6631  f1prex  7018  domssex2  8661  1sdom  8705  marypha1lem  8881  marypha2  8887  isinffi  9405  fseqenlem1  9435  dfac12r  9557  ackbij2  9654  cff1  9669  fin23lem28  9751  fin23lem41  9763  pwfseqlem5  10074  hashf1lem1  13809  gsumzres  19022  gsumzcl2  19023  gsumzf1o  19025  gsumzaddlem  19034  gsumzmhm  19050  gsumzoppg  19057  lindfres  20512  islindf3  20515  dvne0f1  24615  istrkg2ld  26254  ausgrusgrb  26958  uspgrushgr  26968  usgruspgr  26971  uspgr1e  27034  sizusglecusglem1  27251  s1f1  30645  s2f1  30647  qqhre  31371  erdsze2lem1  32563  eldioph2lem2  39702  eldioph2  39703  fundcmpsurbijinjpreimafv  43924  fundcmpsurinjimaid  43928