| Step | Hyp | Ref | Expression | 
						
							| 1 |  | kbass5 |  | 
						
							| 2 |  | kbval |  | 
						
							| 3 | 2 | 3expa |  | 
						
							| 4 | 3 | adantrr |  | 
						
							| 5 | 4 | oveq1d |  | 
						
							| 6 |  | hicl |  | 
						
							| 7 |  | kbmul |  | 
						
							| 8 | 6 7 | syl3an1 |  | 
						
							| 9 | 8 | 3exp |  | 
						
							| 10 | 9 | ex |  | 
						
							| 11 | 10 | com13 |  | 
						
							| 12 | 11 | imp43 |  | 
						
							| 13 |  | bracl |  | 
						
							| 14 |  | bracnln |  | 
						
							| 15 |  | cnvbramul |  | 
						
							| 16 | 13 14 15 | syl2an |  | 
						
							| 17 |  | braval |  | 
						
							| 18 | 17 | fveq2d |  | 
						
							| 19 |  | cnvbrabra |  | 
						
							| 20 | 18 19 | oveqan12d |  | 
						
							| 21 | 16 20 | eqtr2d |  | 
						
							| 22 | 21 | anasss |  | 
						
							| 23 |  | kbass2 |  | 
						
							| 24 | 23 | 3expb |  | 
						
							| 25 | 24 | fveq2d |  | 
						
							| 26 | 22 25 | eqtr2d |  | 
						
							| 27 | 26 | adantll |  | 
						
							| 28 | 27 | oveq2d |  | 
						
							| 29 | 12 28 | eqtr4d |  | 
						
							| 30 | 1 5 29 | 3eqtrd |  |