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

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

Hypothesis | bnj1292.1 | $${\u22a2}{A}={B}\cap {C}$$ | |

Assertion | bnj1292 | $${\u22a2}{A}\subseteq {B}$$ |

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

1 | bnj1292.1 | $${\u22a2}{A}={B}\cap {C}$$ | |

2 | inss1 | $${\u22a2}{B}\cap {C}\subseteq {B}$$ | |

3 | 1 2 | eqsstri | $${\u22a2}{A}\subseteq {B}$$ |