**Description:** 0 is a left identity for addition. (Contributed by Mario Carneiro, 27-May-2016)

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

Hypothesis | muld.1 | $${\u22a2}{\phi}\to {A}\in \u2102$$ | |

Assertion | addid2d | $${\u22a2}{\phi}\to 0+{A}={A}$$ |

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

1 | muld.1 | $${\u22a2}{\phi}\to {A}\in \u2102$$ | |

2 | addid2 | $${\u22a2}{A}\in \u2102\to 0+{A}={A}$$ | |

3 | 1 2 | syl | $${\u22a2}{\phi}\to 0+{A}={A}$$ |