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Theorem psmetxrge0 14284
Description: The distance function of a pseudometric space is a function into the nonnegative extended real numbers. (Contributed by Thierry Arnoux, 24-Feb-2018.)
Assertion
Ref Expression
psmetxrge0  |-  ( D  e.  (PsMet `  X
)  ->  D :
( X  X.  X
) --> ( 0 [,] +oo ) )

Proof of Theorem psmetxrge0
Dummy variable  a is distinct from all other variables.
StepHypRef Expression
1 psmetf 14277 . . 3  |-  ( D  e.  (PsMet `  X
)  ->  D :
( X  X.  X
) --> RR* )
21ffnd 5385 . 2  |-  ( D  e.  (PsMet `  X
)  ->  D  Fn  ( X  X.  X
) )
31ffvelcdmda 5671 . . . . 5  |-  ( ( D  e.  (PsMet `  X )  /\  a  e.  ( X  X.  X
) )  ->  ( D `  a )  e.  RR* )
4 elxp6 6193 . . . . . . . 8  |-  ( a  e.  ( X  X.  X )  <->  ( a  =  <. ( 1st `  a
) ,  ( 2nd `  a ) >.  /\  (
( 1st `  a
)  e.  X  /\  ( 2nd `  a )  e.  X ) ) )
54simprbi 275 . . . . . . 7  |-  ( a  e.  ( X  X.  X )  ->  (
( 1st `  a
)  e.  X  /\  ( 2nd `  a )  e.  X ) )
6 psmetge0 14283 . . . . . . . 8  |-  ( ( D  e.  (PsMet `  X )  /\  ( 1st `  a )  e.  X  /\  ( 2nd `  a )  e.  X
)  ->  0  <_  ( ( 1st `  a
) D ( 2nd `  a ) ) )
763expb 1206 . . . . . . 7  |-  ( ( D  e.  (PsMet `  X )  /\  (
( 1st `  a
)  e.  X  /\  ( 2nd `  a )  e.  X ) )  ->  0  <_  (
( 1st `  a
) D ( 2nd `  a ) ) )
85, 7sylan2 286 . . . . . 6  |-  ( ( D  e.  (PsMet `  X )  /\  a  e.  ( X  X.  X
) )  ->  0  <_  ( ( 1st `  a
) D ( 2nd `  a ) ) )
9 1st2nd2 6199 . . . . . . . . 9  |-  ( a  e.  ( X  X.  X )  ->  a  =  <. ( 1st `  a
) ,  ( 2nd `  a ) >. )
109fveq2d 5538 . . . . . . . 8  |-  ( a  e.  ( X  X.  X )  ->  ( D `  a )  =  ( D `  <. ( 1st `  a
) ,  ( 2nd `  a ) >. )
)
11 df-ov 5898 . . . . . . . 8  |-  ( ( 1st `  a ) D ( 2nd `  a
) )  =  ( D `  <. ( 1st `  a ) ,  ( 2nd `  a
) >. )
1210, 11eqtr4di 2240 . . . . . . 7  |-  ( a  e.  ( X  X.  X )  ->  ( D `  a )  =  ( ( 1st `  a ) D ( 2nd `  a ) ) )
1312adantl 277 . . . . . 6  |-  ( ( D  e.  (PsMet `  X )  /\  a  e.  ( X  X.  X
) )  ->  ( D `  a )  =  ( ( 1st `  a ) D ( 2nd `  a ) ) )
148, 13breqtrrd 4046 . . . . 5  |-  ( ( D  e.  (PsMet `  X )  /\  a  e.  ( X  X.  X
) )  ->  0  <_  ( D `  a
) )
15 elxrge0 10007 . . . . 5  |-  ( ( D `  a )  e.  ( 0 [,] +oo )  <->  ( ( D `
 a )  e. 
RR*  /\  0  <_  ( D `  a ) ) )
163, 14, 15sylanbrc 417 . . . 4  |-  ( ( D  e.  (PsMet `  X )  /\  a  e.  ( X  X.  X
) )  ->  ( D `  a )  e.  ( 0 [,] +oo ) )
1716ralrimiva 2563 . . 3  |-  ( D  e.  (PsMet `  X
)  ->  A. a  e.  ( X  X.  X
) ( D `  a )  e.  ( 0 [,] +oo )
)
18 fnfvrnss 5696 . . 3  |-  ( ( D  Fn  ( X  X.  X )  /\  A. a  e.  ( X  X.  X ) ( D `  a )  e.  ( 0 [,] +oo ) )  ->  ran  D 
C_  ( 0 [,] +oo ) )
192, 17, 18syl2anc 411 . 2  |-  ( D  e.  (PsMet `  X
)  ->  ran  D  C_  ( 0 [,] +oo ) )
20 df-f 5239 . 2  |-  ( D : ( X  X.  X ) --> ( 0 [,] +oo )  <->  ( D  Fn  ( X  X.  X
)  /\  ran  D  C_  ( 0 [,] +oo ) ) )
212, 19, 20sylanbrc 417 1  |-  ( D  e.  (PsMet `  X
)  ->  D :
( X  X.  X
) --> ( 0 [,] +oo ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    = wceq 1364    e. wcel 2160   A.wral 2468    C_ wss 3144   <.cop 3610   class class class wbr 4018    X. cxp 4642   ran crn 4645    Fn wfn 5230   -->wf 5231   ` cfv 5235  (class class class)co 5895   1stc1st 6162   2ndc2nd 6163   0cc0 7840   +oocpnf 8018   RR*cxr 8020    <_ cle 8022   [,]cicc 9920  PsMetcpsmet 13845
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-io 710  ax-5 1458  ax-7 1459  ax-gen 1460  ax-ie1 1504  ax-ie2 1505  ax-8 1515  ax-10 1516  ax-11 1517  ax-i12 1518  ax-bndl 1520  ax-4 1521  ax-17 1537  ax-i9 1541  ax-ial 1545  ax-i5r 1546  ax-13 2162  ax-14 2163  ax-ext 2171  ax-sep 4136  ax-pow 4192  ax-pr 4227  ax-un 4451  ax-setind 4554  ax-cnex 7931  ax-resscn 7932  ax-1cn 7933  ax-1re 7934  ax-icn 7935  ax-addcl 7936  ax-addrcl 7937  ax-mulcl 7938  ax-mulrcl 7939  ax-addcom 7940  ax-mulcom 7941  ax-addass 7942  ax-mulass 7943  ax-distr 7944  ax-i2m1 7945  ax-0lt1 7946  ax-1rid 7947  ax-0id 7948  ax-rnegex 7949  ax-precex 7950  ax-cnre 7951  ax-pre-ltirr 7952  ax-pre-lttrn 7954  ax-pre-ltadd 7956  ax-pre-mulgt0 7957
This theorem depends on definitions:  df-bi 117  df-dc 836  df-3or 981  df-3an 982  df-tru 1367  df-fal 1370  df-nf 1472  df-sb 1774  df-eu 2041  df-mo 2042  df-clab 2176  df-cleq 2182  df-clel 2185  df-nfc 2321  df-ne 2361  df-nel 2456  df-ral 2473  df-rex 2474  df-reu 2475  df-rab 2477  df-v 2754  df-sbc 2978  df-csb 3073  df-dif 3146  df-un 3148  df-in 3150  df-ss 3157  df-if 3550  df-pw 3592  df-sn 3613  df-pr 3614  df-op 3616  df-uni 3825  df-iun 3903  df-br 4019  df-opab 4080  df-mpt 4081  df-id 4311  df-xp 4650  df-rel 4651  df-cnv 4652  df-co 4653  df-dm 4654  df-rn 4655  df-res 4656  df-ima 4657  df-iota 5196  df-fun 5237  df-fn 5238  df-f 5239  df-fv 5243  df-riota 5851  df-ov 5898  df-oprab 5899  df-mpo 5900  df-1st 6164  df-2nd 6165  df-map 6675  df-pnf 8023  df-mnf 8024  df-xr 8025  df-ltxr 8026  df-le 8027  df-sub 8159  df-neg 8160  df-2 9007  df-xadd 9802  df-icc 9924  df-psmet 13853
This theorem is referenced by: (None)
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