| Step | Hyp | Ref | Expression | 
						
							| 1 |  | tmdcn2.1 | ⊢ 𝐵  =  ( Base ‘ 𝐺 ) | 
						
							| 2 |  | tmdcn2.2 | ⊢ 𝐽  =  ( TopOpen ‘ 𝐺 ) | 
						
							| 3 |  | tmdcn2.3 | ⊢  +   =  ( +g ‘ 𝐺 ) | 
						
							| 4 | 2 1 | tmdtopon | ⊢ ( 𝐺  ∈  TopMnd  →  𝐽  ∈  ( TopOn ‘ 𝐵 ) ) | 
						
							| 5 | 4 | ad2antrr | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  𝐽  ∈  ( TopOn ‘ 𝐵 ) ) | 
						
							| 6 |  | eqid | ⊢ ( +𝑓 ‘ 𝐺 )  =  ( +𝑓 ‘ 𝐺 ) | 
						
							| 7 | 2 6 | tmdcn | ⊢ ( 𝐺  ∈  TopMnd  →  ( +𝑓 ‘ 𝐺 )  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) | 
						
							| 8 | 7 | ad2antrr | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ( +𝑓 ‘ 𝐺 )  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 ) ) | 
						
							| 9 |  | simpr1 | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  𝑋  ∈  𝐵 ) | 
						
							| 10 |  | simpr2 | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  𝑌  ∈  𝐵 ) | 
						
							| 11 | 9 10 | opelxpd | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  〈 𝑋 ,  𝑌 〉  ∈  ( 𝐵  ×  𝐵 ) ) | 
						
							| 12 |  | txtopon | ⊢ ( ( 𝐽  ∈  ( TopOn ‘ 𝐵 )  ∧  𝐽  ∈  ( TopOn ‘ 𝐵 ) )  →  ( 𝐽  ×t  𝐽 )  ∈  ( TopOn ‘ ( 𝐵  ×  𝐵 ) ) ) | 
						
							| 13 | 5 5 12 | syl2anc | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ( 𝐽  ×t  𝐽 )  ∈  ( TopOn ‘ ( 𝐵  ×  𝐵 ) ) ) | 
						
							| 14 |  | toponuni | ⊢ ( ( 𝐽  ×t  𝐽 )  ∈  ( TopOn ‘ ( 𝐵  ×  𝐵 ) )  →  ( 𝐵  ×  𝐵 )  =  ∪  ( 𝐽  ×t  𝐽 ) ) | 
						
							| 15 | 13 14 | syl | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ( 𝐵  ×  𝐵 )  =  ∪  ( 𝐽  ×t  𝐽 ) ) | 
						
							| 16 | 11 15 | eleqtrd | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  〈 𝑋 ,  𝑌 〉  ∈  ∪  ( 𝐽  ×t  𝐽 ) ) | 
						
							| 17 |  | eqid | ⊢ ∪  ( 𝐽  ×t  𝐽 )  =  ∪  ( 𝐽  ×t  𝐽 ) | 
						
							| 18 | 17 | cncnpi | ⊢ ( ( ( +𝑓 ‘ 𝐺 )  ∈  ( ( 𝐽  ×t  𝐽 )  Cn  𝐽 )  ∧  〈 𝑋 ,  𝑌 〉  ∈  ∪  ( 𝐽  ×t  𝐽 ) )  →  ( +𝑓 ‘ 𝐺 )  ∈  ( ( ( 𝐽  ×t  𝐽 )  CnP  𝐽 ) ‘ 〈 𝑋 ,  𝑌 〉 ) ) | 
						
							| 19 | 8 16 18 | syl2anc | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ( +𝑓 ‘ 𝐺 )  ∈  ( ( ( 𝐽  ×t  𝐽 )  CnP  𝐽 ) ‘ 〈 𝑋 ,  𝑌 〉 ) ) | 
						
							| 20 |  | simplr | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  𝑈  ∈  𝐽 ) | 
						
							| 21 | 1 3 6 | plusfval | ⊢ ( ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵 )  →  ( 𝑋 ( +𝑓 ‘ 𝐺 ) 𝑌 )  =  ( 𝑋  +  𝑌 ) ) | 
						
							| 22 | 9 10 21 | syl2anc | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ( 𝑋 ( +𝑓 ‘ 𝐺 ) 𝑌 )  =  ( 𝑋  +  𝑌 ) ) | 
						
							| 23 |  | simpr3 | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ( 𝑋  +  𝑌 )  ∈  𝑈 ) | 
						
							| 24 | 22 23 | eqeltrd | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ( 𝑋 ( +𝑓 ‘ 𝐺 ) 𝑌 )  ∈  𝑈 ) | 
						
							| 25 | 5 5 19 20 9 10 24 | txcnpi | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ∃ 𝑢  ∈  𝐽 ∃ 𝑣  ∈  𝐽 ( 𝑋  ∈  𝑢  ∧  𝑌  ∈  𝑣  ∧  ( 𝑢  ×  𝑣 )  ⊆  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 ) ) ) | 
						
							| 26 |  | dfss3 | ⊢ ( ( 𝑢  ×  𝑣 )  ⊆  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 )  ↔  ∀ 𝑧  ∈  ( 𝑢  ×  𝑣 ) 𝑧  ∈  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 ) ) | 
						
							| 27 |  | eleq1 | ⊢ ( 𝑧  =  〈 𝑥 ,  𝑦 〉  →  ( 𝑧  ∈  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 )  ↔  〈 𝑥 ,  𝑦 〉  ∈  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 ) ) ) | 
						
							| 28 | 1 6 | plusffn | ⊢ ( +𝑓 ‘ 𝐺 )  Fn  ( 𝐵  ×  𝐵 ) | 
						
							| 29 |  | elpreima | ⊢ ( ( +𝑓 ‘ 𝐺 )  Fn  ( 𝐵  ×  𝐵 )  →  ( 〈 𝑥 ,  𝑦 〉  ∈  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 )  ↔  ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  ∧  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  ∈  𝑈 ) ) ) | 
						
							| 30 | 28 29 | ax-mp | ⊢ ( 〈 𝑥 ,  𝑦 〉  ∈  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 )  ↔  ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  ∧  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  ∈  𝑈 ) ) | 
						
							| 31 | 27 30 | bitrdi | ⊢ ( 𝑧  =  〈 𝑥 ,  𝑦 〉  →  ( 𝑧  ∈  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 )  ↔  ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  ∧  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  ∈  𝑈 ) ) ) | 
						
							| 32 | 31 | ralxp | ⊢ ( ∀ 𝑧  ∈  ( 𝑢  ×  𝑣 ) 𝑧  ∈  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 )  ↔  ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  ∧  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  ∈  𝑈 ) ) | 
						
							| 33 | 26 32 | bitri | ⊢ ( ( 𝑢  ×  𝑣 )  ⊆  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 )  ↔  ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  ∧  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  ∈  𝑈 ) ) | 
						
							| 34 |  | opelxp | ⊢ ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  ↔  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) ) | 
						
							| 35 |  | df-ov | ⊢ ( 𝑥 ( +𝑓 ‘ 𝐺 ) 𝑦 )  =  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 ) | 
						
							| 36 | 1 3 6 | plusfval | ⊢ ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  →  ( 𝑥 ( +𝑓 ‘ 𝐺 ) 𝑦 )  =  ( 𝑥  +  𝑦 ) ) | 
						
							| 37 | 35 36 | eqtr3id | ⊢ ( ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 )  →  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  =  ( 𝑥  +  𝑦 ) ) | 
						
							| 38 | 34 37 | sylbi | ⊢ ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  →  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  =  ( 𝑥  +  𝑦 ) ) | 
						
							| 39 | 38 | eleq1d | ⊢ ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  →  ( ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  ∈  𝑈  ↔  ( 𝑥  +  𝑦 )  ∈  𝑈 ) ) | 
						
							| 40 | 39 | biimpa | ⊢ ( ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  ∧  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  ∈  𝑈 )  →  ( 𝑥  +  𝑦 )  ∈  𝑈 ) | 
						
							| 41 | 40 | 2ralimi | ⊢ ( ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐵  ×  𝐵 )  ∧  ( ( +𝑓 ‘ 𝐺 ) ‘ 〈 𝑥 ,  𝑦 〉 )  ∈  𝑈 )  →  ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 𝑥  +  𝑦 )  ∈  𝑈 ) | 
						
							| 42 | 33 41 | sylbi | ⊢ ( ( 𝑢  ×  𝑣 )  ⊆  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 )  →  ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 𝑥  +  𝑦 )  ∈  𝑈 ) | 
						
							| 43 | 42 | 3anim3i | ⊢ ( ( 𝑋  ∈  𝑢  ∧  𝑌  ∈  𝑣  ∧  ( 𝑢  ×  𝑣 )  ⊆  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 ) )  →  ( 𝑋  ∈  𝑢  ∧  𝑌  ∈  𝑣  ∧  ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 𝑥  +  𝑦 )  ∈  𝑈 ) ) | 
						
							| 44 | 43 | reximi | ⊢ ( ∃ 𝑣  ∈  𝐽 ( 𝑋  ∈  𝑢  ∧  𝑌  ∈  𝑣  ∧  ( 𝑢  ×  𝑣 )  ⊆  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 ) )  →  ∃ 𝑣  ∈  𝐽 ( 𝑋  ∈  𝑢  ∧  𝑌  ∈  𝑣  ∧  ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 𝑥  +  𝑦 )  ∈  𝑈 ) ) | 
						
							| 45 | 44 | reximi | ⊢ ( ∃ 𝑢  ∈  𝐽 ∃ 𝑣  ∈  𝐽 ( 𝑋  ∈  𝑢  ∧  𝑌  ∈  𝑣  ∧  ( 𝑢  ×  𝑣 )  ⊆  ( ◡ ( +𝑓 ‘ 𝐺 )  “  𝑈 ) )  →  ∃ 𝑢  ∈  𝐽 ∃ 𝑣  ∈  𝐽 ( 𝑋  ∈  𝑢  ∧  𝑌  ∈  𝑣  ∧  ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 𝑥  +  𝑦 )  ∈  𝑈 ) ) | 
						
							| 46 | 25 45 | syl | ⊢ ( ( ( 𝐺  ∈  TopMnd  ∧  𝑈  ∈  𝐽 )  ∧  ( 𝑋  ∈  𝐵  ∧  𝑌  ∈  𝐵  ∧  ( 𝑋  +  𝑌 )  ∈  𝑈 ) )  →  ∃ 𝑢  ∈  𝐽 ∃ 𝑣  ∈  𝐽 ( 𝑋  ∈  𝑢  ∧  𝑌  ∈  𝑣  ∧  ∀ 𝑥  ∈  𝑢 ∀ 𝑦  ∈  𝑣 ( 𝑥  +  𝑦 )  ∈  𝑈 ) ) |