| ampersand-intro | Given a sentence (at line m) and a sentence (at line n), conclude a conjunction of them. |
| Annotation: m, n &I | |
| Assumption set: The union of the assumption sets at lines m and n. | |
| Comment: The order of lines m and n in the proof is irrelevant. | |
| Also known as:Conjunction (CONJ). | |
| Example. | |
1 (1) P A | |
2 (2) Q A | |
1,2 (3) P & Q 1,2 &I | |
1,2 (3) Q & P 1,2 &I | |