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Theorem dgrmul 21712
Description: The degree of a product of nonzero polynomials is the sum of degrees. (Contributed by Mario Carneiro, 24-Jul-2014.)
Hypotheses
Ref Expression
dgradd.1  |-  M  =  (deg `  F )
dgradd.2  |-  N  =  (deg `  G )
Assertion
Ref Expression
dgrmul  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  (deg `  ( F  oF  x.  G
) )  =  ( M  +  N ) )

Proof of Theorem dgrmul
StepHypRef Expression
1 dgradd.1 . . . 4  |-  M  =  (deg `  F )
2 dgradd.2 . . . 4  |-  N  =  (deg `  G )
31, 2dgrmul2 21711 . . 3  |-  ( ( F  e.  (Poly `  S )  /\  G  e.  (Poly `  S )
)  ->  (deg `  ( F  oF  x.  G
) )  <_  ( M  +  N )
)
43ad2ant2r 746 . 2  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  (deg `  ( F  oF  x.  G
) )  <_  ( M  +  N )
)
5 plymulcl 21664 . . . 4  |-  ( ( F  e.  (Poly `  S )  /\  G  e.  (Poly `  S )
)  ->  ( F  oF  x.  G
)  e.  (Poly `  CC ) )
65ad2ant2r 746 . . 3  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( F  oF  x.  G )  e.  (Poly `  CC )
)
7 dgrcl 21676 . . . . . 6  |-  ( F  e.  (Poly `  S
)  ->  (deg `  F
)  e.  NN0 )
81, 7syl5eqel 2522 . . . . 5  |-  ( F  e.  (Poly `  S
)  ->  M  e.  NN0 )
98ad2antrr 725 . . . 4  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  M  e.  NN0 )
10 dgrcl 21676 . . . . . 6  |-  ( G  e.  (Poly `  S
)  ->  (deg `  G
)  e.  NN0 )
112, 10syl5eqel 2522 . . . . 5  |-  ( G  e.  (Poly `  S
)  ->  N  e.  NN0 )
1211ad2antrl 727 . . . 4  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  N  e.  NN0 )
139, 12nn0addcld 10632 . . 3  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( M  +  N )  e.  NN0 )
14 eqid 2438 . . . . . 6  |-  (coeff `  F )  =  (coeff `  F )
15 eqid 2438 . . . . . 6  |-  (coeff `  G )  =  (coeff `  G )
1614, 15, 1, 2coemulhi 21696 . . . . 5  |-  ( ( F  e.  (Poly `  S )  /\  G  e.  (Poly `  S )
)  ->  ( (coeff `  ( F  oF  x.  G ) ) `
 ( M  +  N ) )  =  ( ( (coeff `  F ) `  M
)  x.  ( (coeff `  G ) `  N
) ) )
1716ad2ant2r 746 . . . 4  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( (coeff `  ( F  oF  x.  G ) ) `  ( M  +  N
) )  =  ( ( (coeff `  F
) `  M )  x.  ( (coeff `  G
) `  N )
) )
1814coef3 21675 . . . . . . 7  |-  ( F  e.  (Poly `  S
)  ->  (coeff `  F
) : NN0 --> CC )
1918ad2antrr 725 . . . . . 6  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  (coeff `  F
) : NN0 --> CC )
2019, 9ffvelrnd 5839 . . . . 5  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( (coeff `  F ) `  M
)  e.  CC )
2115coef3 21675 . . . . . . 7  |-  ( G  e.  (Poly `  S
)  ->  (coeff `  G
) : NN0 --> CC )
2221ad2antrl 727 . . . . . 6  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  (coeff `  G
) : NN0 --> CC )
2322, 12ffvelrnd 5839 . . . . 5  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( (coeff `  G ) `  N
)  e.  CC )
241, 14dgreq0 21707 . . . . . . . 8  |-  ( F  e.  (Poly `  S
)  ->  ( F  =  0p  <->  ( (coeff `  F ) `  M
)  =  0 ) )
2524necon3bid 2638 . . . . . . 7  |-  ( F  e.  (Poly `  S
)  ->  ( F  =/=  0p  <->  ( (coeff `  F ) `  M
)  =/=  0 ) )
2625biimpa 484 . . . . . 6  |-  ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  -> 
( (coeff `  F
) `  M )  =/=  0 )
2726adantr 465 . . . . 5  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( (coeff `  F ) `  M
)  =/=  0 )
282, 15dgreq0 21707 . . . . . . . 8  |-  ( G  e.  (Poly `  S
)  ->  ( G  =  0p  <->  ( (coeff `  G ) `  N
)  =  0 ) )
2928necon3bid 2638 . . . . . . 7  |-  ( G  e.  (Poly `  S
)  ->  ( G  =/=  0p  <->  ( (coeff `  G ) `  N
)  =/=  0 ) )
3029biimpa 484 . . . . . 6  |-  ( ( G  e.  (Poly `  S )  /\  G  =/=  0p )  -> 
( (coeff `  G
) `  N )  =/=  0 )
3130adantl 466 . . . . 5  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( (coeff `  G ) `  N
)  =/=  0 )
3220, 23, 27, 31mulne0d 9980 . . . 4  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( ( (coeff `  F ) `  M
)  x.  ( (coeff `  G ) `  N
) )  =/=  0
)
3317, 32eqnetrd 2621 . . 3  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( (coeff `  ( F  oF  x.  G ) ) `  ( M  +  N
) )  =/=  0
)
34 eqid 2438 . . . 4  |-  (coeff `  ( F  oF  x.  G ) )  =  (coeff `  ( F  oF  x.  G
) )
35 eqid 2438 . . . 4  |-  (deg `  ( F  oF  x.  G ) )  =  (deg `  ( F  oF  x.  G
) )
3634, 35dgrub 21677 . . 3  |-  ( ( ( F  oF  x.  G )  e.  (Poly `  CC )  /\  ( M  +  N
)  e.  NN0  /\  ( (coeff `  ( F  oF  x.  G
) ) `  ( M  +  N )
)  =/=  0 )  ->  ( M  +  N )  <_  (deg `  ( F  oF  x.  G ) ) )
376, 13, 33, 36syl3anc 1218 . 2  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( M  +  N )  <_  (deg `  ( F  oF  x.  G ) ) )
38 dgrcl 21676 . . . . 5  |-  ( ( F  oF  x.  G )  e.  (Poly `  CC )  ->  (deg `  ( F  oF  x.  G ) )  e.  NN0 )
396, 38syl 16 . . . 4  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  (deg `  ( F  oF  x.  G
) )  e.  NN0 )
4039nn0red 10629 . . 3  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  (deg `  ( F  oF  x.  G
) )  e.  RR )
4113nn0red 10629 . . 3  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( M  +  N )  e.  RR )
4240, 41letri3d 9508 . 2  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  ( (deg `  ( F  oF  x.  G ) )  =  ( M  +  N
)  <->  ( (deg `  ( F  oF  x.  G ) )  <_ 
( M  +  N
)  /\  ( M  +  N )  <_  (deg `  ( F  oF  x.  G ) ) ) ) )
434, 37, 42mpbir2and 913 1  |-  ( ( ( F  e.  (Poly `  S )  /\  F  =/=  0p )  /\  ( G  e.  (Poly `  S )  /\  G  =/=  0p ) )  ->  (deg `  ( F  oF  x.  G
) )  =  ( M  +  N ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    /\ wa 369    = wceq 1369    e. wcel 1756    =/= wne 2601   class class class wbr 4287   -->wf 5409   ` cfv 5413  (class class class)co 6086    oFcof 6313   CCcc 9272   0cc0 9274    + caddc 9277    x. cmul 9279    <_ cle 9411   NN0cn0 10571   0pc0p 21122  Polycply 21627  coeffccoe 21629  degcdgr 21630
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1591  ax-4 1602  ax-5 1670  ax-6 1708  ax-7 1728  ax-8 1758  ax-9 1760  ax-10 1775  ax-11 1780  ax-12 1792  ax-13 1943  ax-ext 2419  ax-rep 4398  ax-sep 4408  ax-nul 4416  ax-pow 4465  ax-pr 4526  ax-un 6367  ax-inf2 7839  ax-cnex 9330  ax-resscn 9331  ax-1cn 9332  ax-icn 9333  ax-addcl 9334  ax-addrcl 9335  ax-mulcl 9336  ax-mulrcl 9337  ax-mulcom 9338  ax-addass 9339  ax-mulass 9340  ax-distr 9341  ax-i2m1 9342  ax-1ne0 9343  ax-1rid 9344  ax-rnegex 9345  ax-rrecex 9346  ax-cnre 9347  ax-pre-lttri 9348  ax-pre-lttrn 9349  ax-pre-ltadd 9350  ax-pre-mulgt0 9351  ax-pre-sup 9352  ax-addf 9353
This theorem depends on definitions:  df-bi 185  df-or 370  df-an 371  df-3or 966  df-3an 967  df-tru 1372  df-fal 1375  df-ex 1587  df-nf 1590  df-sb 1701  df-eu 2256  df-mo 2257  df-clab 2425  df-cleq 2431  df-clel 2434  df-nfc 2563  df-ne 2603  df-nel 2604  df-ral 2715  df-rex 2716  df-reu 2717  df-rmo 2718  df-rab 2719  df-v 2969  df-sbc 3182  df-csb 3284  df-dif 3326  df-un 3328  df-in 3330  df-ss 3337  df-pss 3339  df-nul 3633  df-if 3787  df-pw 3857  df-sn 3873  df-pr 3875  df-tp 3877  df-op 3879  df-uni 4087  df-int 4124  df-iun 4168  df-br 4288  df-opab 4346  df-mpt 4347  df-tr 4381  df-eprel 4627  df-id 4631  df-po 4636  df-so 4637  df-fr 4674  df-se 4675  df-we 4676  df-ord 4717  df-on 4718  df-lim 4719  df-suc 4720  df-xp 4841  df-rel 4842  df-cnv 4843  df-co 4844  df-dm 4845  df-rn 4846  df-res 4847  df-ima 4848  df-iota 5376  df-fun 5415  df-fn 5416  df-f 5417  df-f1 5418  df-fo 5419  df-f1o 5420  df-fv 5421  df-isom 5422  df-riota 6047  df-ov 6089  df-oprab 6090  df-mpt2 6091  df-of 6315  df-om 6472  df-1st 6572  df-2nd 6573  df-recs 6824  df-rdg 6858  df-1o 6912  df-oadd 6916  df-er 7093  df-map 7208  df-pm 7209  df-en 7303  df-dom 7304  df-sdom 7305  df-fin 7306  df-sup 7683  df-oi 7716  df-card 8101  df-pnf 9412  df-mnf 9413  df-xr 9414  df-ltxr 9415  df-le 9416  df-sub 9589  df-neg 9590  df-div 9986  df-nn 10315  df-2 10372  df-3 10373  df-n0 10572  df-z 10639  df-uz 10854  df-rp 10984  df-fz 11430  df-fzo 11541  df-fl 11634  df-seq 11799  df-exp 11858  df-hash 12096  df-cj 12580  df-re 12581  df-im 12582  df-sqr 12716  df-abs 12717  df-clim 12958  df-rlim 12959  df-sum 13156  df-0p 21123  df-ply 21631  df-coe 21633  df-dgr 21634
This theorem is referenced by:  dgrmulc  21713  dgrcolem1  21715  plydivlem4  21737  plydiveu  21739  fta1lem  21748  quotcan  21750  vieta1lem1  21751  vieta1lem2  21752
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