Description: Associative law for four conjunctions with a triple conjunction. (Contributed by Thierry Arnoux, 21-Jan-2025)
Ref | Expression | ||
---|---|---|---|
Assertion | 13an22anass |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | an2anr | ||
2 | an2anr | ||
3 | an4 | ||
4 | 2 3 | bitri | |
5 | an43 | ||
6 | 1 4 5 | 3bitr2ri | |
7 | 3an4anass | ||
8 | ancom | ||
9 | 6 7 8 | 3bitr2ri |