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| Description: An open set is a subset
of a metric space which includes a ball around
each of its points. Definition 1.3-2 of [Kreyszig] p. 18. The
object |
| Ref | Expression |
|---|---|
| opnfval.1 |
|
| opnfval.2 |
|
| Ref | Expression |
|---|---|
| opnfval |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | dmexg 3364 |
. . . . . 6
| |
| 2 | dmexg 3364 |
. . . . . 6
| |
| 3 | 1, 2 | syl 10 |
. . . . 5
|
| 4 | opnfval.1 |
. . . . 5
| |
| 5 | 3, 4 | syl5eqel 1555 |
. . . 4
|
| 6 | abssexg 2753 |
. . . 4
| |
| 7 | 5, 6 | syl 10 |
. . 3
|
| 8 | dmeq 3317 |
. . . . . . . . 9
| |
| 9 | 8 | dmeqd 3319 |
. . . . . . . 8
|
| 10 | 9, 4 | syl6eqr 1528 |
. . . . . . 7
|
| 11 | 10 | sseq2d 2092 |
. . . . . 6
|
| 12 | fveq2 3730 |
. . . . . . . . 9
| |
| 13 | 12 | rneqd 3347 |
. . . . . . . 8
|
| 14 | 13 | rexeq1d 1793 |
. . . . . . 7
|
| 15 | 14 | ralbidv 1666 |
. . . . . 6
|
| 16 | 11, 15 | anbi12d 630 |
. . . . 5
|
| 17 | 16 | abbidv 1580 |
. . . 4
|
| 18 | df-opn 7793 |
. . . 4
| |
| 19 | 17, 18 | fvopab4g 3785 |
. . 3
|
| 20 | 7, 19 | mpdan 706 |
. 2
|
| 21 | opnfval.2 |
. 2
| |
| 22 | 20, 21 | syl5eq 1522 |
1
|
| Colors of variables: wff set class |
| Syntax hints: |
| This theorem is referenced by: opnfss 7855 isopn 7856 |
| This theorem was proved from axioms: ax-1 4 ax-2 5 ax-3 6 ax-mp 7 ax-7 964 ax-gen 965 ax-8 966 ax-9 967 ax-10 968 ax-11 969 ax-12 970 ax-13 971 ax-14 972 ax-17 973 ax-4 975 ax-5o 977 ax-6o 980 ax-9o 1125 ax-10o 1142 ax-16 1212 ax-11o 1220 ax-ext 1462 ax-sep 2708 ax-pow 2748 ax-pr 2785 ax-un 2872 |
| This theorem depends on definitions: df-bi 147 df-or 224 df-an 225 df-ex 983 df-sb 1174 df-eu 1384 df-mo 1385 df-clab 1467 df-cleq 1472 df-clel 1475 df-ne 1590 df-ral 1652 df-rex 1653 df-rab 1655 df-v 1815 df-dif 2052 df-un 2053 df-in 2054 df-ss 2056 df-nul 2284 df-pw 2406 df-sn 2416 df-pr 2417 df-op 2420 df-uni 2508 df-br 2625 df-opab 2672 df-id 2841 df-xp 3190 df-rel 3191 df-cnv 3192 df-co 3193 df-dm 3194 df-rn 3195 df-res 3196 df-ima 3197 df-fun 3198 df-fv 3204 df-opn 7793 |