| Step | Hyp | Ref | Expression | 
						
							| 1 |  | uspgrupgr | ⊢ ( 𝐺  ∈  USPGraph  →  𝐺  ∈  UPGraph ) | 
						
							| 2 |  | uspgrushgr | ⊢ ( 𝐺  ∈  USPGraph  →  𝐺  ∈  USHGraph ) | 
						
							| 3 | 1 2 | jca | ⊢ ( 𝐺  ∈  USPGraph  →  ( 𝐺  ∈  UPGraph  ∧  𝐺  ∈  USHGraph ) ) | 
						
							| 4 |  | eqid | ⊢ ( Vtx ‘ 𝐺 )  =  ( Vtx ‘ 𝐺 ) | 
						
							| 5 |  | eqid | ⊢ ( iEdg ‘ 𝐺 )  =  ( iEdg ‘ 𝐺 ) | 
						
							| 6 | 4 5 | ushgrf | ⊢ ( 𝐺  ∈  USHGraph  →  ( iEdg ‘ 𝐺 ) : dom  ( iEdg ‘ 𝐺 ) –1-1→ ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } ) ) | 
						
							| 7 |  | edgval | ⊢ ( Edg ‘ 𝐺 )  =  ran  ( iEdg ‘ 𝐺 ) | 
						
							| 8 |  | upgredgss | ⊢ ( 𝐺  ∈  UPGraph  →  ( Edg ‘ 𝐺 )  ⊆  { 𝑥  ∈  ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } )  ∣  ( ♯ ‘ 𝑥 )  ≤  2 } ) | 
						
							| 9 | 7 8 | eqsstrrid | ⊢ ( 𝐺  ∈  UPGraph  →  ran  ( iEdg ‘ 𝐺 )  ⊆  { 𝑥  ∈  ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } )  ∣  ( ♯ ‘ 𝑥 )  ≤  2 } ) | 
						
							| 10 |  | f1ssr | ⊢ ( ( ( iEdg ‘ 𝐺 ) : dom  ( iEdg ‘ 𝐺 ) –1-1→ ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } )  ∧  ran  ( iEdg ‘ 𝐺 )  ⊆  { 𝑥  ∈  ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } )  ∣  ( ♯ ‘ 𝑥 )  ≤  2 } )  →  ( iEdg ‘ 𝐺 ) : dom  ( iEdg ‘ 𝐺 ) –1-1→ { 𝑥  ∈  ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } )  ∣  ( ♯ ‘ 𝑥 )  ≤  2 } ) | 
						
							| 11 | 6 9 10 | syl2anr | ⊢ ( ( 𝐺  ∈  UPGraph  ∧  𝐺  ∈  USHGraph )  →  ( iEdg ‘ 𝐺 ) : dom  ( iEdg ‘ 𝐺 ) –1-1→ { 𝑥  ∈  ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } )  ∣  ( ♯ ‘ 𝑥 )  ≤  2 } ) | 
						
							| 12 | 4 5 | isuspgr | ⊢ ( 𝐺  ∈  UPGraph  →  ( 𝐺  ∈  USPGraph  ↔  ( iEdg ‘ 𝐺 ) : dom  ( iEdg ‘ 𝐺 ) –1-1→ { 𝑥  ∈  ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } )  ∣  ( ♯ ‘ 𝑥 )  ≤  2 } ) ) | 
						
							| 13 | 12 | adantr | ⊢ ( ( 𝐺  ∈  UPGraph  ∧  𝐺  ∈  USHGraph )  →  ( 𝐺  ∈  USPGraph  ↔  ( iEdg ‘ 𝐺 ) : dom  ( iEdg ‘ 𝐺 ) –1-1→ { 𝑥  ∈  ( 𝒫  ( Vtx ‘ 𝐺 )  ∖  { ∅ } )  ∣  ( ♯ ‘ 𝑥 )  ≤  2 } ) ) | 
						
							| 14 | 11 13 | mpbird | ⊢ ( ( 𝐺  ∈  UPGraph  ∧  𝐺  ∈  USHGraph )  →  𝐺  ∈  USPGraph ) | 
						
							| 15 | 3 14 | impbii | ⊢ ( 𝐺  ∈  USPGraph  ↔  ( 𝐺  ∈  UPGraph  ∧  𝐺  ∈  USHGraph ) ) |