| Step | Hyp | Ref | Expression | 
						
							| 1 |  | drngnzr | ⊢ ( 𝑅  ∈  DivRing  →  𝑅  ∈  NzRing ) | 
						
							| 2 |  | eqid | ⊢ ( Base ‘ 𝑅 )  =  ( Base ‘ 𝑅 ) | 
						
							| 3 |  | eqid | ⊢ ( Unit ‘ 𝑅 )  =  ( Unit ‘ 𝑅 ) | 
						
							| 4 |  | eqid | ⊢ ( 0g ‘ 𝑅 )  =  ( 0g ‘ 𝑅 ) | 
						
							| 5 | 2 3 4 | isdrng | ⊢ ( 𝑅  ∈  DivRing  ↔  ( 𝑅  ∈  Ring  ∧  ( Unit ‘ 𝑅 )  =  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) ) ) | 
						
							| 6 | 5 | simprbi | ⊢ ( 𝑅  ∈  DivRing  →  ( Unit ‘ 𝑅 )  =  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } ) ) | 
						
							| 7 |  | drngring | ⊢ ( 𝑅  ∈  DivRing  →  𝑅  ∈  Ring ) | 
						
							| 8 |  | eqid | ⊢ ( RLReg ‘ 𝑅 )  =  ( RLReg ‘ 𝑅 ) | 
						
							| 9 | 8 3 | unitrrg | ⊢ ( 𝑅  ∈  Ring  →  ( Unit ‘ 𝑅 )  ⊆  ( RLReg ‘ 𝑅 ) ) | 
						
							| 10 | 7 9 | syl | ⊢ ( 𝑅  ∈  DivRing  →  ( Unit ‘ 𝑅 )  ⊆  ( RLReg ‘ 𝑅 ) ) | 
						
							| 11 | 6 10 | eqsstrrd | ⊢ ( 𝑅  ∈  DivRing  →  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } )  ⊆  ( RLReg ‘ 𝑅 ) ) | 
						
							| 12 | 2 8 4 | isdomn2 | ⊢ ( 𝑅  ∈  Domn  ↔  ( 𝑅  ∈  NzRing  ∧  ( ( Base ‘ 𝑅 )  ∖  { ( 0g ‘ 𝑅 ) } )  ⊆  ( RLReg ‘ 𝑅 ) ) ) | 
						
							| 13 | 1 11 12 | sylanbrc | ⊢ ( 𝑅  ∈  DivRing  →  𝑅  ∈  Domn ) |