| Step | Hyp | Ref | Expression | 
						
							| 1 |  | rng2idlring.r | ⊢ ( 𝜑  →  𝑅  ∈  Rng ) | 
						
							| 2 |  | rng2idlring.i | ⊢ ( 𝜑  →  𝐼  ∈  ( 2Ideal ‘ 𝑅 ) ) | 
						
							| 3 |  | rng2idlring.j | ⊢ 𝐽  =  ( 𝑅  ↾s  𝐼 ) | 
						
							| 4 |  | rng2idlring.u | ⊢ ( 𝜑  →  𝐽  ∈  Ring ) | 
						
							| 5 |  | rng2idlring.b | ⊢ 𝐵  =  ( Base ‘ 𝑅 ) | 
						
							| 6 |  | rng2idlring.t | ⊢  ·   =  ( .r ‘ 𝑅 ) | 
						
							| 7 |  | rng2idlring.1 | ⊢  1   =  ( 1r ‘ 𝐽 ) | 
						
							| 8 | 2 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  𝐼  ∈  ( 2Ideal ‘ 𝑅 ) ) | 
						
							| 9 | 3 6 | ressmulr | ⊢ ( 𝐼  ∈  ( 2Ideal ‘ 𝑅 )  →   ·   =  ( .r ‘ 𝐽 ) ) | 
						
							| 10 | 8 9 | syl | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →   ·   =  ( .r ‘ 𝐽 ) ) | 
						
							| 11 | 10 | oveqd | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( (  1   ·  𝐴 )  ·   1  )  =  ( (  1   ·  𝐴 ) ( .r ‘ 𝐽 )  1  ) ) | 
						
							| 12 |  | eqid | ⊢ ( Base ‘ 𝐽 )  =  ( Base ‘ 𝐽 ) | 
						
							| 13 |  | eqid | ⊢ ( .r ‘ 𝐽 )  =  ( .r ‘ 𝐽 ) | 
						
							| 14 | 4 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  𝐽  ∈  Ring ) | 
						
							| 15 | 1 2 3 4 5 6 7 | rngqiprngghmlem1 | ⊢ ( ( 𝜑  ∧  𝐴  ∈  𝐵 )  →  (  1   ·  𝐴 )  ∈  ( Base ‘ 𝐽 ) ) | 
						
							| 16 | 15 | adantrr | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  (  1   ·  𝐴 )  ∈  ( Base ‘ 𝐽 ) ) | 
						
							| 17 | 12 13 7 14 16 | ringridmd | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( (  1   ·  𝐴 ) ( .r ‘ 𝐽 )  1  )  =  (  1   ·  𝐴 ) ) | 
						
							| 18 | 11 17 | eqtrd | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( (  1   ·  𝐴 )  ·   1  )  =  (  1   ·  𝐴 ) ) | 
						
							| 19 | 18 | oveq1d | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( ( (  1   ·  𝐴 )  ·   1  )  ·  𝐶 )  =  ( (  1   ·  𝐴 )  ·  𝐶 ) ) | 
						
							| 20 | 1 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  𝑅  ∈  Rng ) | 
						
							| 21 | 1 2 3 4 5 6 7 | rngqiprng1elbas | ⊢ ( 𝜑  →   1   ∈  𝐵 ) | 
						
							| 22 | 21 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →   1   ∈  𝐵 ) | 
						
							| 23 |  | simprl | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  𝐴  ∈  𝐵 ) | 
						
							| 24 | 5 6 | rngcl | ⊢ ( ( 𝑅  ∈  Rng  ∧   1   ∈  𝐵  ∧  𝐴  ∈  𝐵 )  →  (  1   ·  𝐴 )  ∈  𝐵 ) | 
						
							| 25 | 20 22 23 24 | syl3anc | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  (  1   ·  𝐴 )  ∈  𝐵 ) | 
						
							| 26 |  | simprr | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  𝐶  ∈  𝐵 ) | 
						
							| 27 | 5 6 | rngass | ⊢ ( ( 𝑅  ∈  Rng  ∧  ( (  1   ·  𝐴 )  ∈  𝐵  ∧   1   ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( ( (  1   ·  𝐴 )  ·   1  )  ·  𝐶 )  =  ( (  1   ·  𝐴 )  ·  (  1   ·  𝐶 ) ) ) | 
						
							| 28 | 20 25 22 26 27 | syl13anc | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( ( (  1   ·  𝐴 )  ·   1  )  ·  𝐶 )  =  ( (  1   ·  𝐴 )  ·  (  1   ·  𝐶 ) ) ) | 
						
							| 29 | 5 6 | rngass | ⊢ ( ( 𝑅  ∈  Rng  ∧  (  1   ∈  𝐵  ∧  𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( (  1   ·  𝐴 )  ·  𝐶 )  =  (  1   ·  ( 𝐴  ·  𝐶 ) ) ) | 
						
							| 30 | 20 22 23 26 29 | syl13anc | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( (  1   ·  𝐴 )  ·  𝐶 )  =  (  1   ·  ( 𝐴  ·  𝐶 ) ) ) | 
						
							| 31 | 19 28 30 | 3eqtr3d | ⊢ ( ( 𝜑  ∧  ( 𝐴  ∈  𝐵  ∧  𝐶  ∈  𝐵 ) )  →  ( (  1   ·  𝐴 )  ·  (  1   ·  𝐶 ) )  =  (  1   ·  ( 𝐴  ·  𝐶 ) ) ) |