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Theorem axi9 2581
Description: Axiom of existence (intuitionistic logic axiom ax-i9). In classical logic, this is equivalent to ax-6 1873 but in intuitionistic logic it needs to be stated using the existential quantifier. (Contributed by Jim Kingdon, 31-Dec-2017.) (New usage is discouraged.)
Ref Expression
axi9 𝑥 𝑥 = 𝑦

Proof of Theorem axi9
StepHypRef Expression
1 ax6e 2232 1 𝑥 𝑥 = 𝑦
Colors of variables: wff setvar class
Syntax hints:  wex 1694
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1711  ax-4 1726  ax-5 1825  ax-6 1873  ax-7 1920  ax-12 2031  ax-13 2228
This theorem depends on definitions:  df-bi 195  df-an 384  df-ex 1695
This theorem is referenced by: (None)
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