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Theorem bcval3 11580
Description: Value of the binomial coefficient,  N choose  K, outside of its standard domain. Remark in [Gleason] p. 295. (Contributed by NM, 14-Jul-2005.) (Revised by Mario Carneiro, 8-Nov-2013.)
Assertion
Ref Expression
bcval3  |-  ( ( N  e.  NN0  /\  K  e.  ZZ  /\  -.  K  e.  ( 0 ... N ) )  ->  ( N  _C  K )  =  0 )

Proof of Theorem bcval3
StepHypRef Expression
1 bcval 11578 . . 3  |-  ( ( N  e.  NN0  /\  K  e.  ZZ )  ->  ( N  _C  K
)  =  if ( K  e.  ( 0 ... N ) ,  ( ( ! `  N )  /  (
( ! `  ( N  -  K )
)  x.  ( ! `
 K ) ) ) ,  0 ) )
213adant3 977 . 2  |-  ( ( N  e.  NN0  /\  K  e.  ZZ  /\  -.  K  e.  ( 0 ... N ) )  ->  ( N  _C  K )  =  if ( K  e.  ( 0 ... N ) ,  ( ( ! `
 N )  / 
( ( ! `  ( N  -  K
) )  x.  ( ! `  K )
) ) ,  0 ) )
3 iffalse 3733 . . 3  |-  ( -.  K  e.  ( 0 ... N )  ->  if ( K  e.  ( 0 ... N ) ,  ( ( ! `
 N )  / 
( ( ! `  ( N  -  K
) )  x.  ( ! `  K )
) ) ,  0 )  =  0 )
433ad2ant3 980 . 2  |-  ( ( N  e.  NN0  /\  K  e.  ZZ  /\  -.  K  e.  ( 0 ... N ) )  ->  if ( K  e.  ( 0 ... N ) ,  ( ( ! `  N
)  /  ( ( ! `  ( N  -  K ) )  x.  ( ! `  K ) ) ) ,  0 )  =  0 )
52, 4eqtrd 2462 1  |-  ( ( N  e.  NN0  /\  K  e.  ZZ  /\  -.  K  e.  ( 0 ... N ) )  ->  ( N  _C  K )  =  0 )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    /\ w3a 936    = wceq 1652    e. wcel 1725   ifcif 3726   ` cfv 5440  (class class class)co 6067   0cc0 8974    x. cmul 8979    - cmin 9275    / cdiv 9661   NN0cn0 10205   ZZcz 10266   ...cfz 11027   !cfa 11549    _C cbc 11576
This theorem is referenced by:  bcval4  11581  bccmpl  11583  bcval5  11592  bcpasc  11595  bccl  11596  hashbc  11685  binomlem  12591
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1555  ax-5 1566  ax-17 1626  ax-9 1666  ax-8 1687  ax-14 1729  ax-6 1744  ax-7 1749  ax-11 1761  ax-12 1950  ax-ext 2411  ax-sep 4317  ax-nul 4325  ax-pr 4390  ax-1cn 9032  ax-icn 9033  ax-addcl 9034  ax-mulcl 9036  ax-i2m1 9042
This theorem depends on definitions:  df-bi 178  df-or 360  df-an 361  df-3an 938  df-tru 1328  df-ex 1551  df-nf 1554  df-sb 1659  df-eu 2284  df-mo 2285  df-clab 2417  df-cleq 2423  df-clel 2426  df-nfc 2555  df-ne 2595  df-ral 2697  df-rex 2698  df-rab 2701  df-v 2945  df-sbc 3149  df-dif 3310  df-un 3312  df-in 3314  df-ss 3321  df-nul 3616  df-if 3727  df-sn 3807  df-pr 3808  df-op 3810  df-uni 4003  df-br 4200  df-opab 4254  df-id 4485  df-xp 4870  df-rel 4871  df-cnv 4872  df-co 4873  df-dm 4874  df-iota 5404  df-fun 5442  df-fv 5448  df-ov 6070  df-oprab 6071  df-mpt2 6072  df-bc 11577
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