| Step | Hyp | Ref | Expression | 
						
							| 1 |  | issubrgd.s | ⊢ ( 𝜑  →  𝑆  =  ( 𝐼  ↾s  𝐷 ) ) | 
						
							| 2 |  | issubrgd.z | ⊢ ( 𝜑  →   0   =  ( 0g ‘ 𝐼 ) ) | 
						
							| 3 |  | issubrgd.p | ⊢ ( 𝜑  →   +   =  ( +g ‘ 𝐼 ) ) | 
						
							| 4 |  | issubrgd.ss | ⊢ ( 𝜑  →  𝐷  ⊆  ( Base ‘ 𝐼 ) ) | 
						
							| 5 |  | issubrgd.zcl | ⊢ ( 𝜑  →   0   ∈  𝐷 ) | 
						
							| 6 |  | issubrgd.acl | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐷  ∧  𝑦  ∈  𝐷 )  →  ( 𝑥  +  𝑦 )  ∈  𝐷 ) | 
						
							| 7 |  | issubrgd.ncl | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐷 )  →  ( ( invg ‘ 𝐼 ) ‘ 𝑥 )  ∈  𝐷 ) | 
						
							| 8 |  | issubrgd.o | ⊢ ( 𝜑  →   1   =  ( 1r ‘ 𝐼 ) ) | 
						
							| 9 |  | issubrgd.t | ⊢ ( 𝜑  →   ·   =  ( .r ‘ 𝐼 ) ) | 
						
							| 10 |  | issubrgd.ocl | ⊢ ( 𝜑  →   1   ∈  𝐷 ) | 
						
							| 11 |  | issubrgd.tcl | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐷  ∧  𝑦  ∈  𝐷 )  →  ( 𝑥  ·  𝑦 )  ∈  𝐷 ) | 
						
							| 12 |  | issubrgd.g | ⊢ ( 𝜑  →  𝐼  ∈  Ring ) | 
						
							| 13 |  | ringgrp | ⊢ ( 𝐼  ∈  Ring  →  𝐼  ∈  Grp ) | 
						
							| 14 | 12 13 | syl | ⊢ ( 𝜑  →  𝐼  ∈  Grp ) | 
						
							| 15 | 1 2 3 4 5 6 7 14 | issubgrpd2 | ⊢ ( 𝜑  →  𝐷  ∈  ( SubGrp ‘ 𝐼 ) ) | 
						
							| 16 | 8 10 | eqeltrrd | ⊢ ( 𝜑  →  ( 1r ‘ 𝐼 )  ∈  𝐷 ) | 
						
							| 17 | 9 | oveqdr | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐷  ∧  𝑦  ∈  𝐷 ) )  →  ( 𝑥  ·  𝑦 )  =  ( 𝑥 ( .r ‘ 𝐼 ) 𝑦 ) ) | 
						
							| 18 | 11 | 3expb | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐷  ∧  𝑦  ∈  𝐷 ) )  →  ( 𝑥  ·  𝑦 )  ∈  𝐷 ) | 
						
							| 19 | 17 18 | eqeltrrd | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐷  ∧  𝑦  ∈  𝐷 ) )  →  ( 𝑥 ( .r ‘ 𝐼 ) 𝑦 )  ∈  𝐷 ) | 
						
							| 20 | 19 | ralrimivva | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐷 ∀ 𝑦  ∈  𝐷 ( 𝑥 ( .r ‘ 𝐼 ) 𝑦 )  ∈  𝐷 ) | 
						
							| 21 |  | eqid | ⊢ ( Base ‘ 𝐼 )  =  ( Base ‘ 𝐼 ) | 
						
							| 22 |  | eqid | ⊢ ( 1r ‘ 𝐼 )  =  ( 1r ‘ 𝐼 ) | 
						
							| 23 |  | eqid | ⊢ ( .r ‘ 𝐼 )  =  ( .r ‘ 𝐼 ) | 
						
							| 24 | 21 22 23 | issubrg2 | ⊢ ( 𝐼  ∈  Ring  →  ( 𝐷  ∈  ( SubRing ‘ 𝐼 )  ↔  ( 𝐷  ∈  ( SubGrp ‘ 𝐼 )  ∧  ( 1r ‘ 𝐼 )  ∈  𝐷  ∧  ∀ 𝑥  ∈  𝐷 ∀ 𝑦  ∈  𝐷 ( 𝑥 ( .r ‘ 𝐼 ) 𝑦 )  ∈  𝐷 ) ) ) | 
						
							| 25 | 12 24 | syl | ⊢ ( 𝜑  →  ( 𝐷  ∈  ( SubRing ‘ 𝐼 )  ↔  ( 𝐷  ∈  ( SubGrp ‘ 𝐼 )  ∧  ( 1r ‘ 𝐼 )  ∈  𝐷  ∧  ∀ 𝑥  ∈  𝐷 ∀ 𝑦  ∈  𝐷 ( 𝑥 ( .r ‘ 𝐼 ) 𝑦 )  ∈  𝐷 ) ) ) | 
						
							| 26 | 15 16 20 25 | mpbir3and | ⊢ ( 𝜑  →  𝐷  ∈  ( SubRing ‘ 𝐼 ) ) |