Description: Commutative/associative law that swaps the first two factors in a triple product. (Contributed by Mario Carneiro, 27-May-2016)
Ref | Expression | ||
---|---|---|---|
Hypotheses | muld.1 | |
|
addcomd.2 | |
||
addcand.3 | |
||
Assertion | mul12d | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | muld.1 | |
|
2 | addcomd.2 | |
|
3 | addcand.3 | |
|
4 | mul12 | |
|
5 | 1 2 3 4 | syl3anc | |