Theorem baseval 17309

Description: Value of the base set extractor. (Normally it is preferred to work with (Base‘ndx) rather than the hard-coded 1 in order to make structure theorems portable. This is an example of how to obtain it when needed.) (New usage is discouraged.) (Contributed by NM, 4-Sep-2011.)

Hypothesis

Ref	Expression
baseval.k	⊢ 𝐾 ∈ V

Assertion

Ref	Expression
baseval	⊢ (Base‘𝐾) = (𝐾‘1)

Proof of Theorem baseval

Step	Hyp	Ref	Expression
1		baseval.k	. 2 ⊢ 𝐾 ∈ V
2		df-base 17308	. 2 ⊢ Base = Slot 1
3	1, 2	strfvn 17284	1 ⊢ (Base‘𝐾) = (𝐾‘1)

This proof depends on syntax axioms:   = wceq 1570   ∈ wcel 2145  Vcvv 3453  ‘cfv 6537  1c1 11129  Basecbs 17307

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-10 2178  ax-11 2194  ax-12 2215  ax-ext 2734  ax-sep 5255  ax-nul 5267  ax-pr 5402

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2566  df-eu 2596  df-clab 2741  df-cleq 2754  df-clel 2837  df-nfc 2911  df-ne 2958  df-ral 3079  df-rex 3089  df-rab 3415  df-v 3455  df-dif 3905  df-un 3907  df-in 3909  df-ss 3919  df-nul 4283  df-if 4486  df-sn 4588  df-pr 4590  df-op 4594  df-uni 4871  df-br 5108  df-opab 5172  df-mpt 5191  df-id 5554  df-xp 5665  df-rel 5666  df-cnv 5667  df-co 5668  df-dm 5669  df-iota 6493  df-fun 6539  df-fv 6545  df-slot 17280  df-base 17308

This theorem is used by: (None)