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Theorem exbtwnzlemex 10394
Description: Existence of an integer so that a given real number is between the integer and its successor. The real number must satisfy the  n  <_  A  \/  A  <  n hypothesis. For example either a rational number or a number which is irrational (in the sense of being apart from any rational number) will meet this condition.

The proof starts by finding two integers which are less than and greater than  A. Then this range can be shrunk by choosing an integer in between the endpoints of the range and then deciding which half of the range to keep based on the  n  <_  A  \/  A  <  n hypothesis, and iterating until the range consists of two consecutive integers. (Contributed by Jim Kingdon, 8-Oct-2021.)

Hypotheses
Ref Expression
exbtwnzlemex.a  |-  ( ph  ->  A  e.  RR )
exbtwnzlemex.tri  |-  ( (
ph  /\  n  e.  ZZ )  ->  ( n  <_  A  \/  A  <  n ) )
Assertion
Ref Expression
exbtwnzlemex  |-  ( ph  ->  E. x  e.  ZZ  ( x  <_  A  /\  A  <  ( x  + 
1 ) ) )
Distinct variable groups:    A, n    x, A    ph, n
Allowed substitution hint:    ph( x)

Proof of Theorem exbtwnzlemex
Dummy variables  a  j  m  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 exbtwnzlemex.a . . . 4  |-  ( ph  ->  A  e.  RR )
2 btwnz 9494 . . . 4  |-  ( A  e.  RR  ->  ( E. m  e.  ZZ  m  <  A  /\  E. j  e.  ZZ  A  <  j ) )
31, 2syl 14 . . 3  |-  ( ph  ->  ( E. m  e.  ZZ  m  <  A  /\  E. j  e.  ZZ  A  <  j ) )
4 reeanv 2676 . . 3  |-  ( E. m  e.  ZZ  E. j  e.  ZZ  (
m  <  A  /\  A  <  j )  <->  ( E. m  e.  ZZ  m  <  A  /\  E. j  e.  ZZ  A  <  j
) )
53, 4sylibr 134 . 2  |-  ( ph  ->  E. m  e.  ZZ  E. j  e.  ZZ  (
m  <  A  /\  A  <  j ) )
6 simplrl 535 . . . . . 6  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  m  e.  ZZ )
76zred 9497 . . . . . . 7  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  m  e.  RR )
81ad2antrr 488 . . . . . . 7  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  A  e.  RR )
9 simprl 529 . . . . . . 7  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  m  <  A )
107, 8, 9ltled 8193 . . . . . 6  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  m  <_  A )
11 simprr 531 . . . . . . 7  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  A  <  j )
126zcnd 9498 . . . . . . . 8  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  m  e.  CC )
13 simplrr 536 . . . . . . . . 9  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  -> 
j  e.  ZZ )
1413zcnd 9498 . . . . . . . 8  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  -> 
j  e.  CC )
1512, 14pncan3d 8388 . . . . . . 7  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  -> 
( m  +  ( j  -  m ) )  =  j )
1611, 15breqtrrd 4073 . . . . . 6  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  A  <  ( m  +  ( j  -  m
) ) )
17 breq1 4048 . . . . . . . 8  |-  ( y  =  m  ->  (
y  <_  A  <->  m  <_  A ) )
18 oveq1 5953 . . . . . . . . 9  |-  ( y  =  m  ->  (
y  +  ( j  -  m ) )  =  ( m  +  ( j  -  m
) ) )
1918breq2d 4057 . . . . . . . 8  |-  ( y  =  m  ->  ( A  <  ( y  +  ( j  -  m
) )  <->  A  <  ( m  +  ( j  -  m ) ) ) )
2017, 19anbi12d 473 . . . . . . 7  |-  ( y  =  m  ->  (
( y  <_  A  /\  A  <  ( y  +  ( j  -  m ) ) )  <-> 
( m  <_  A  /\  A  <  ( m  +  ( j  -  m ) ) ) ) )
2120rspcev 2877 . . . . . 6  |-  ( ( m  e.  ZZ  /\  ( m  <_  A  /\  A  <  ( m  +  ( j  -  m
) ) ) )  ->  E. y  e.  ZZ  ( y  <_  A  /\  A  <  ( y  +  ( j  -  m ) ) ) )
226, 10, 16, 21syl12anc 1248 . . . . 5  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  E. y  e.  ZZ  ( y  <_  A  /\  A  <  ( y  +  ( j  -  m ) ) ) )
2313zred 9497 . . . . . . . 8  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  -> 
j  e.  RR )
247, 8, 23, 9, 11lttrd 8200 . . . . . . 7  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  m  <  j )
25 znnsub 9426 . . . . . . . 8  |-  ( ( m  e.  ZZ  /\  j  e.  ZZ )  ->  ( m  <  j  <->  ( j  -  m )  e.  NN ) )
2625ad2antlr 489 . . . . . . 7  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  -> 
( m  <  j  <->  ( j  -  m )  e.  NN ) )
2724, 26mpbid 147 . . . . . 6  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  -> 
( j  -  m
)  e.  NN )
28 exbtwnzlemex.tri . . . . . . . . . 10  |-  ( (
ph  /\  n  e.  ZZ )  ->  ( n  <_  A  \/  A  <  n ) )
2928ralrimiva 2579 . . . . . . . . 9  |-  ( ph  ->  A. n  e.  ZZ  ( n  <_  A  \/  A  <  n ) )
30 breq1 4048 . . . . . . . . . . 11  |-  ( n  =  a  ->  (
n  <_  A  <->  a  <_  A ) )
31 breq2 4049 . . . . . . . . . . 11  |-  ( n  =  a  ->  ( A  <  n  <->  A  <  a ) )
3230, 31orbi12d 795 . . . . . . . . . 10  |-  ( n  =  a  ->  (
( n  <_  A  \/  A  <  n )  <-> 
( a  <_  A  \/  A  <  a ) ) )
3332cbvralv 2738 . . . . . . . . 9  |-  ( A. n  e.  ZZ  (
n  <_  A  \/  A  <  n )  <->  A. a  e.  ZZ  ( a  <_  A  \/  A  <  a ) )
3429, 33sylib 122 . . . . . . . 8  |-  ( ph  ->  A. a  e.  ZZ  ( a  <_  A  \/  A  <  a ) )
3534ad2antrr 488 . . . . . . 7  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  A. a  e.  ZZ  ( a  <_  A  \/  A  <  a ) )
3635r19.21bi 2594 . . . . . 6  |-  ( ( ( ( ph  /\  ( m  e.  ZZ  /\  j  e.  ZZ ) )  /\  ( m  <  A  /\  A  <  j ) )  /\  a  e.  ZZ )  ->  ( a  <_  A  \/  A  <  a ) )
3727, 8, 36exbtwnzlemshrink 10393 . . . . 5  |-  ( ( ( ( ph  /\  ( m  e.  ZZ  /\  j  e.  ZZ ) )  /\  ( m  <  A  /\  A  <  j ) )  /\  E. y  e.  ZZ  (
y  <_  A  /\  A  <  ( y  +  ( j  -  m
) ) ) )  ->  E. x  e.  ZZ  ( x  <_  A  /\  A  <  ( x  + 
1 ) ) )
3822, 37mpdan 421 . . . 4  |-  ( ( ( ph  /\  (
m  e.  ZZ  /\  j  e.  ZZ )
)  /\  ( m  <  A  /\  A  < 
j ) )  ->  E. x  e.  ZZ  ( x  <_  A  /\  A  <  ( x  + 
1 ) ) )
3938ex 115 . . 3  |-  ( (
ph  /\  ( m  e.  ZZ  /\  j  e.  ZZ ) )  -> 
( ( m  < 
A  /\  A  <  j )  ->  E. x  e.  ZZ  ( x  <_  A  /\  A  <  (
x  +  1 ) ) ) )
4039rexlimdvva 2631 . 2  |-  ( ph  ->  ( E. m  e.  ZZ  E. j  e.  ZZ  ( m  < 
A  /\  A  <  j )  ->  E. x  e.  ZZ  ( x  <_  A  /\  A  <  (
x  +  1 ) ) ) )
415, 40mpd 13 1  |-  ( ph  ->  E. x  e.  ZZ  ( x  <_  A  /\  A  <  ( x  + 
1 ) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    <-> wb 105    \/ wo 710    e. wcel 2176   A.wral 2484   E.wrex 2485   class class class wbr 4045  (class class class)co 5946   RRcr 7926   1c1 7928    + caddc 7930    < clt 8109    <_ cle 8110    - cmin 8245   NNcn 9038   ZZcz 9374
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 711  ax-5 1470  ax-7 1471  ax-gen 1472  ax-ie1 1516  ax-ie2 1517  ax-8 1527  ax-10 1528  ax-11 1529  ax-i12 1530  ax-bndl 1532  ax-4 1533  ax-17 1549  ax-i9 1553  ax-ial 1557  ax-i5r 1558  ax-13 2178  ax-14 2179  ax-ext 2187  ax-sep 4163  ax-pow 4219  ax-pr 4254  ax-un 4481  ax-setind 4586  ax-cnex 8018  ax-resscn 8019  ax-1cn 8020  ax-1re 8021  ax-icn 8022  ax-addcl 8023  ax-addrcl 8024  ax-mulcl 8025  ax-addcom 8027  ax-addass 8029  ax-distr 8031  ax-i2m1 8032  ax-0lt1 8033  ax-0id 8035  ax-rnegex 8036  ax-cnre 8038  ax-pre-ltirr 8039  ax-pre-ltwlin 8040  ax-pre-lttrn 8041  ax-pre-ltadd 8043  ax-arch 8046
This theorem depends on definitions:  df-bi 117  df-3or 982  df-3an 983  df-tru 1376  df-fal 1379  df-nf 1484  df-sb 1786  df-eu 2057  df-mo 2058  df-clab 2192  df-cleq 2198  df-clel 2201  df-nfc 2337  df-ne 2377  df-nel 2472  df-ral 2489  df-rex 2490  df-reu 2491  df-rab 2493  df-v 2774  df-sbc 2999  df-dif 3168  df-un 3170  df-in 3172  df-ss 3179  df-pw 3618  df-sn 3639  df-pr 3640  df-op 3642  df-uni 3851  df-int 3886  df-br 4046  df-opab 4107  df-id 4341  df-xp 4682  df-rel 4683  df-cnv 4684  df-co 4685  df-dm 4686  df-iota 5233  df-fun 5274  df-fv 5280  df-riota 5901  df-ov 5949  df-oprab 5950  df-mpo 5951  df-pnf 8111  df-mnf 8112  df-xr 8113  df-ltxr 8114  df-le 8115  df-sub 8247  df-neg 8248  df-inn 9039  df-n0 9298  df-z 9375
This theorem is referenced by:  qbtwnz  10396  apbtwnz  10419
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