Step |
Hyp |
Ref |
Expression |
1 |
|
eqid |
|- ( ( subringAlg ` E ) ` ( Base ` K ) ) = ( ( subringAlg ` E ) ` ( Base ` K ) ) |
2 |
|
eqid |
|- ( ( subringAlg ` E ) ` ( Base ` F ) ) = ( ( subringAlg ` E ) ` ( Base ` F ) ) |
3 |
|
eqid |
|- ( ( subringAlg ` ( E |`s ( Base ` F ) ) ) ` ( Base ` K ) ) = ( ( subringAlg ` ( E |`s ( Base ` F ) ) ) ` ( Base ` K ) ) |
4 |
|
eqid |
|- ( E |`s ( Base ` F ) ) = ( E |`s ( Base ` F ) ) |
5 |
|
eqid |
|- ( E |`s ( Base ` K ) ) = ( E |`s ( Base ` K ) ) |
6 |
|
simpl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> E /FldExt F ) |
7 |
|
fldextfld1 |
|- ( E /FldExt F -> E e. Field ) |
8 |
6 7
|
syl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> E e. Field ) |
9 |
|
isfld |
|- ( E e. Field <-> ( E e. DivRing /\ E e. CRing ) ) |
10 |
9
|
simplbi |
|- ( E e. Field -> E e. DivRing ) |
11 |
8 10
|
syl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> E e. DivRing ) |
12 |
|
fldextfld1 |
|- ( F /FldExt K -> F e. Field ) |
13 |
12
|
adantl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> F e. Field ) |
14 |
|
brfldext |
|- ( ( E e. Field /\ F e. Field ) -> ( E /FldExt F <-> ( F = ( E |`s ( Base ` F ) ) /\ ( Base ` F ) e. ( SubRing ` E ) ) ) ) |
15 |
8 13 14
|
syl2anc |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( E /FldExt F <-> ( F = ( E |`s ( Base ` F ) ) /\ ( Base ` F ) e. ( SubRing ` E ) ) ) ) |
16 |
6 15
|
mpbid |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( F = ( E |`s ( Base ` F ) ) /\ ( Base ` F ) e. ( SubRing ` E ) ) ) |
17 |
16
|
simpld |
|- ( ( E /FldExt F /\ F /FldExt K ) -> F = ( E |`s ( Base ` F ) ) ) |
18 |
|
isfld |
|- ( F e. Field <-> ( F e. DivRing /\ F e. CRing ) ) |
19 |
18
|
simplbi |
|- ( F e. Field -> F e. DivRing ) |
20 |
13 19
|
syl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> F e. DivRing ) |
21 |
17 20
|
eqeltrrd |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( E |`s ( Base ` F ) ) e. DivRing ) |
22 |
|
fldexttr |
|- ( ( E /FldExt F /\ F /FldExt K ) -> E /FldExt K ) |
23 |
|
fldextfld2 |
|- ( F /FldExt K -> K e. Field ) |
24 |
23
|
adantl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> K e. Field ) |
25 |
|
brfldext |
|- ( ( E e. Field /\ K e. Field ) -> ( E /FldExt K <-> ( K = ( E |`s ( Base ` K ) ) /\ ( Base ` K ) e. ( SubRing ` E ) ) ) ) |
26 |
8 24 25
|
syl2anc |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( E /FldExt K <-> ( K = ( E |`s ( Base ` K ) ) /\ ( Base ` K ) e. ( SubRing ` E ) ) ) ) |
27 |
22 26
|
mpbid |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( K = ( E |`s ( Base ` K ) ) /\ ( Base ` K ) e. ( SubRing ` E ) ) ) |
28 |
27
|
simpld |
|- ( ( E /FldExt F /\ F /FldExt K ) -> K = ( E |`s ( Base ` K ) ) ) |
29 |
|
isfld |
|- ( K e. Field <-> ( K e. DivRing /\ K e. CRing ) ) |
30 |
29
|
simplbi |
|- ( K e. Field -> K e. DivRing ) |
31 |
24 30
|
syl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> K e. DivRing ) |
32 |
28 31
|
eqeltrrd |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( E |`s ( Base ` K ) ) e. DivRing ) |
33 |
16
|
simprd |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( Base ` F ) e. ( SubRing ` E ) ) |
34 |
|
eqid |
|- ( Base ` K ) = ( Base ` K ) |
35 |
34
|
fldextsubrg |
|- ( F /FldExt K -> ( Base ` K ) e. ( SubRing ` F ) ) |
36 |
35
|
adantl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( Base ` K ) e. ( SubRing ` F ) ) |
37 |
17
|
fveq2d |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( SubRing ` F ) = ( SubRing ` ( E |`s ( Base ` F ) ) ) ) |
38 |
36 37
|
eleqtrd |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( Base ` K ) e. ( SubRing ` ( E |`s ( Base ` F ) ) ) ) |
39 |
1 2 3 4 5 11 21 32 33 38
|
fedgmul |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( dim ` ( ( subringAlg ` E ) ` ( Base ` K ) ) ) = ( ( dim ` ( ( subringAlg ` E ) ` ( Base ` F ) ) ) *e ( dim ` ( ( subringAlg ` ( E |`s ( Base ` F ) ) ) ` ( Base ` K ) ) ) ) ) |
40 |
|
extdgval |
|- ( E /FldExt K -> ( E [:] K ) = ( dim ` ( ( subringAlg ` E ) ` ( Base ` K ) ) ) ) |
41 |
22 40
|
syl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( E [:] K ) = ( dim ` ( ( subringAlg ` E ) ` ( Base ` K ) ) ) ) |
42 |
|
extdgval |
|- ( E /FldExt F -> ( E [:] F ) = ( dim ` ( ( subringAlg ` E ) ` ( Base ` F ) ) ) ) |
43 |
6 42
|
syl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( E [:] F ) = ( dim ` ( ( subringAlg ` E ) ` ( Base ` F ) ) ) ) |
44 |
|
extdgval |
|- ( F /FldExt K -> ( F [:] K ) = ( dim ` ( ( subringAlg ` F ) ` ( Base ` K ) ) ) ) |
45 |
44
|
adantl |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( F [:] K ) = ( dim ` ( ( subringAlg ` F ) ` ( Base ` K ) ) ) ) |
46 |
17
|
fveq2d |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( subringAlg ` F ) = ( subringAlg ` ( E |`s ( Base ` F ) ) ) ) |
47 |
46
|
fveq1d |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( ( subringAlg ` F ) ` ( Base ` K ) ) = ( ( subringAlg ` ( E |`s ( Base ` F ) ) ) ` ( Base ` K ) ) ) |
48 |
47
|
fveq2d |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( dim ` ( ( subringAlg ` F ) ` ( Base ` K ) ) ) = ( dim ` ( ( subringAlg ` ( E |`s ( Base ` F ) ) ) ` ( Base ` K ) ) ) ) |
49 |
45 48
|
eqtrd |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( F [:] K ) = ( dim ` ( ( subringAlg ` ( E |`s ( Base ` F ) ) ) ` ( Base ` K ) ) ) ) |
50 |
43 49
|
oveq12d |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( ( E [:] F ) *e ( F [:] K ) ) = ( ( dim ` ( ( subringAlg ` E ) ` ( Base ` F ) ) ) *e ( dim ` ( ( subringAlg ` ( E |`s ( Base ` F ) ) ) ` ( Base ` K ) ) ) ) ) |
51 |
39 41 50
|
3eqtr4d |
|- ( ( E /FldExt F /\ F /FldExt K ) -> ( E [:] K ) = ( ( E [:] F ) *e ( F [:] K ) ) ) |