**Description:** First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref | Expression | ||
---|---|---|---|

Hypotheses | bnj101.1 | $${\u22a2}\exists {x}\phantom{\rule{.4em}{0ex}}{\phi}$$ | |

bnj101.2 | $${\u22a2}{\phi}\to {\psi}$$ | ||

Assertion | bnj101 | $${\u22a2}\exists {x}\phantom{\rule{.4em}{0ex}}{\psi}$$ |

Step | Hyp | Ref | Expression |
---|---|---|---|

1 | bnj101.1 | $${\u22a2}\exists {x}\phantom{\rule{.4em}{0ex}}{\phi}$$ | |

2 | bnj101.2 | $${\u22a2}{\phi}\to {\psi}$$ | |

3 | 1 2 | eximii | $${\u22a2}\exists {x}\phantom{\rule{.4em}{0ex}}{\psi}$$ |