Theorem csbnest1gOLD 3189

Description: Nest the composition of two substitutions. Obsolete as of 11-Nov-2016. (Contributed by NM, 23-May-2006.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
csbnest1gOLD	⊢ ((A ∈ V ∧ ∀x B ∈ W) → [A / x][B / x]C = [[A / x]B / x]C)

Distinct variable group:   x,A

Allowed substitution hints:   B(x)   C(x)   V(x)   W(x)

Proof of Theorem csbnest1gOLD

Step	Hyp	Ref	Expression
1		csbnest1g 3188	. 2 ⊢ (A ∈ V → [A / x][B / x]C = [[A / x]B / x]C)
2	1	adantr 451	1 ⊢ ((A ∈ V ∧ ∀x B ∈ W) → [A / x][B / x]C = [[A / x]B / x]C)

Syntax hints:   → wi 4   ∧ wa 358  ∀wal 1540   = wceq 1642   ∈ wcel 1710  [csb 3136

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3an 936  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-v 2861  df-sbc 3047  df-csb 3137

This theorem is referenced by: (None)