:: INTEGRA3 semantic presentation

Lemma1: for b1 being Real
for b2 being FinSequence of REAL st b1 in dom b2 holds
( 1 <= b1 & b1 <= len b2 )
proof end;

Lemma2: for b1 being Real holds b1 - 1 <= b1
by XREAL_1:148;

Lemma3: for b1 being Nat holds (b1 -' b1) + 1 = 1
proof end;

Lemma4: for b1 being Nat st 1 <= b1 & b1 <= 2 & not b1 = 1 holds
b1 = 2
proof end;

theorem Th1: :: INTEGRA3:1
for b1 being closed-interval Subset of REAL
for b2 being Element of divs b1 st vol b1 <> 0 holds
ex b3 being Nat st
( b3 in dom b2 & vol (divset b2,b3) > 0 )
proof end;

theorem Th2: :: INTEGRA3:2
for b1 being Real
for b2 being closed-interval Subset of REAL
for b3 being Element of divs b2 st b1 in b2 holds
ex b4 being Nat st
( b4 in dom b3 & b1 in divset b3,b4 )
proof end;

theorem Th3: :: INTEGRA3:3
for b1 being closed-interval Subset of REAL
for b2, b3 being Element of divs b1 ex b4 being Element of divs b1 st
( b2 <= b4 & b3 <= b4 & rng b4 = (rng b2) \/ (rng b3) )
proof end;

theorem Th4: :: INTEGRA3:4
for b1 being closed-interval Subset of REAL
for b2, b3 being Element of divs b1 st delta b3 < min (rng (upper_volume (chi b1,b1),b2)) holds
for b4, b5 being Real
for b6 being Nat st b6 in dom b3 & b4 in (rng b2) /\ (divset b3,b6) & b5 in (rng b2) /\ (divset b3,b6) holds
b4 = b5
proof end;

theorem Th5: :: INTEGRA3:5
for b1, b2 being FinSequence of REAL st rng b1 = rng b2 & b1 is increasing & b2 is increasing holds
b1 = b2
proof end;

theorem Th6: :: INTEGRA3:6
for b1, b2 being Nat
for b3 being closed-interval Subset of REAL
for b4, b5 being Element of divs b3 st b4 <= b5 & b1 in dom b4 & b2 in dom b4 & b1 <= b2 holds
( indx b5,b4,b1 <= indx b5,b4,b2 & indx b5,b4,b1 in dom b5 )
proof end;

theorem Th7: :: INTEGRA3:7
for b1, b2 being Nat
for b3 being closed-interval Subset of REAL
for b4, b5 being Element of divs b3 st b4 <= b5 & b1 in dom b4 & b2 in dom b4 & b1 < b2 holds
indx b5,b4,b1 < indx b5,b4,b2
proof end;

theorem Th8: :: INTEGRA3:8
for b1 being closed-interval Subset of REAL
for b2 being Element of divs b1 holds delta b2 >= 0
proof end;

Lemma13: for b1 being closed-interval Subset of REAL
for b2 being Function of b1, REAL st b2 is_bounded_on b1 holds
sup (rng b2) >= inf (rng b2)
proof end;

Lemma14: for b1, b2 being closed-interval Subset of REAL
for b3 being Function of b1, REAL st b3 is_bounded_on b1 & b2 c= b1 holds
( inf (rng (b3 | b2)) >= inf (rng b3) & inf (rng b3) <= sup (rng (b3 | b2)) & sup (rng (b3 | b2)) <= sup (rng b3) & inf (rng (b3 | b2)) <= sup (rng b3) )
proof end;

Lemma15: for b1 being Nat
for b2 being closed-interval Subset of REAL
for b3 being Element of divs b2 st b1 in dom b3 holds
vol (divset b3,b1) <= delta b3
proof end;

Lemma16: for b1 being Real
for b2 being closed-interval Subset of REAL
for b3 being Nat
for b4, b5 being Element of divs b2 st b3 = (len b4) - 1 & b1 in divset b4,(len b4) & len b4 >= 2 & b4 <= b5 & rng b5 = (rng b4) \/ {b1} holds
rng (b5 | (indx b5,b4,b3)) = rng (b4 | b3)
proof end;

theorem Th9: :: INTEGRA3:9
for b1 being Real
for b2 being closed-interval Subset of REAL
for b3 being Function of b2, REAL
for b4, b5 being Element of divs b2 st b1 in divset b4,(len b4) & len b4 >= 2 & b4 <= b5 & rng b5 = (rng b4) \/ {b1} & b3 is_bounded_on b2 holds
(Sum (lower_volume b3,b5)) - (Sum (lower_volume b3,b4)) <= ((sup (rng b3)) - (inf (rng b3))) * (delta b4)
proof end;

theorem Th10: :: INTEGRA3:10
for b1 being Real
for b2 being closed-interval Subset of REAL
for b3 being Function of b2, REAL
for b4, b5 being Element of divs b2 st b1 in divset b4,(len b4) & len b4 >= 2 & b4 <= b5 & rng b5 = (rng b4) \/ {b1} & b3 is_bounded_on b2 holds
(Sum (upper_volume b3,b4)) - (Sum (upper_volume b3,b5)) <= ((sup (rng b3)) - (inf (rng b3))) * (delta b4)
proof end;

Lemma19: for b1 being Real
for b2 being closed-interval Subset of REAL
for b3 being PartFunc of b2, REAL st vol b2 <> 0 & b1 in rng (lower_sum_set b3) holds
ex b4 being Element of divs b2 st
( b4 in dom (lower_sum_set b3) & b1 = (lower_sum_set b3) . b4 & b4 . 1 > inf b2 )
proof end;

theorem Th11: :: INTEGRA3:11
for b1 being closed-interval Subset of REAL
for b2 being Element of divs b1
for b3 being Real
for b4, b5 being Nat st b4 in dom b2 & b5 in dom b2 & b4 <= b5 & b3 < (mid b2,b4,b5) . 1 holds
ex b6 being closed-interval Subset of REAL st
( b3 = inf b6 & sup b6 = (mid b2,b4,b5) . (len (mid b2,b4,b5)) & len (mid b2,b4,b5) = (b5 - b4) + 1 & mid b2,b4,b5 is DivisionPoint of b6 )
proof end;

Lemma21: for b1 being closed-interval Subset of REAL
for b2 being Element of divs b1 st vol b1 <> 0 & len b2 = 1 holds
<*(inf b1)*> ^ b2 is non empty increasing FinSequence of REAL
proof end;

Lemma22: for b1 being closed-interval Subset of REAL
for b2 being Element of divs b1 st inf b1 < b2 . 1 holds
<*(inf b1)*> ^ b2 is non empty increasing FinSequence of REAL
proof end;

Lemma23: for b1 being closed-interval Subset of REAL
for b2 being PartFunc of b1, REAL
for b3, b4 being Element of divs b1 st b4 = <*(inf b1)*> ^ b3 holds
( ( for b5 being Nat st b5 in Seg (len b3) holds
divset b4,(b5 + 1) = divset b3,b5 ) & upper_volume b2,b3 = (upper_volume b2,b4) /^ 1 & lower_volume b2,b3 = (lower_volume b2,b4) /^ 1 )
proof end;

Lemma24: for b1 being closed-interval Subset of REAL
for b2, b3 being Element of divs b1 st b3 = <*(inf b1)*> ^ b2 holds
vol (divset b3,1) = 0
proof end;

Lemma25: for b1 being closed-interval Subset of REAL
for b2 being Function of b1, REAL
for b3, b4 being Element of divs b1 st b4 = <*(inf b1)*> ^ b3 holds
delta b4 = delta b3
proof end;

theorem Th12: :: INTEGRA3:12
for b1 being Real
for b2 being closed-interval Subset of REAL
for b3 being Function of b2, REAL
for b4, b5 being Element of divs b2 st b1 in divset b4,(len b4) & vol b2 <> 0 & b4 <= b5 & rng b5 = (rng b4) \/ {b1} & b3 is_bounded_on b2 & b1 > inf b2 holds
(Sum (lower_volume b3,b5)) - (Sum (lower_volume b3,b4)) <= ((sup (rng b3)) - (inf (rng b3))) * (delta b4)
proof end;

theorem Th13: :: INTEGRA3:13
for b1 being Real
for b2 being closed-interval Subset of REAL
for b3 being Function of b2, REAL
for b4, b5 being Element of divs b2 st b1 in divset b4,(len b4) & vol b2 <> 0 & b4 <= b5 & rng b5 = (rng b4) \/ {b1} & b3 is_bounded_on b2 & b1 > inf b2 holds
(Sum (upper_volume b3,b4)) - (Sum (upper_volume b3,b5)) <= ((sup (rng b3)) - (inf (rng b3))) * (delta b4)
proof end;

theorem Th14: :: INTEGRA3:14
for b1 being closed-interval Subset of REAL
for b2, b3 being Element of divs b1
for b4 being Real
for b5, b6 being Nat st b5 in dom b2 & b6 in dom b2 & b5 <= b6 & b2 <= b3 & b4 < (mid b3,(indx b3,b2,b5),(indx b3,b2,b6)) . 1 holds
ex b7 being closed-interval Subset of REAL ex b8, b9 being Element of divs b7 st
( b4 = inf b7 & sup b7 = b9 . (len b9) & sup b7 = b8 . (len b8) & b8 <= b9 & b8 = mid b2,b5,b6 & b9 = mid b3,(indx b3,b2,b5),(indx b3,b2,b6) )
proof end;

theorem Th15: :: INTEGRA3:15
for b1 being Real
for b2 being closed-interval Subset of REAL
for b3 being Element of divs b2 st b1 in rng b3 holds
( b3 . 1 <= b1 & b1 <= b3 . (len b3) )
proof end;

theorem Th16: :: INTEGRA3:16
for b1 being FinSequence of REAL
for b2, b3, b4 being Nat st b1 is increasing & b2 in dom b1 & b3 in dom b1 & b4 in dom b1 & b1 . b2 <= b1 . b4 & b1 . b4 <= b1 . b3 holds
b1 . b4 in rng (mid b1,b2,b3)
proof end;

theorem Th17: :: INTEGRA3:17
for b1 being Nat
for b2 being closed-interval Subset of REAL
for b3 being Function of b2, REAL
for b4 being Element of divs b2 st b3 is_bounded_on b2 & b1 in dom b4 holds
inf (rng (b3 | (divset b4,b1))) <= sup (rng b3)
proof end;

theorem Th18: :: INTEGRA3:18
for b1 being Nat
for b2 being closed-interval Subset of REAL
for b3 being Function of b2, REAL
for b4 being Element of divs b2 st b3 is_bounded_on b2 & b1 in dom b4 holds
sup (rng (b3 | (divset b4,b1))) >= inf (rng b3)
proof end;

theorem Th19: :: INTEGRA3:19
for b1 being closed-interval Subset of REAL
for b2 being Function of b1, REAL
for b3 being DivSequence of b1 st b2 is_bounded_on b1 & delta b3 is convergent_to_0 & vol b1 <> 0 holds
( lower_sum b2,b3 is convergent & lim (lower_sum b2,b3) = lower_integral b2 )
proof end;

theorem Th20: :: INTEGRA3:20
for b1 being closed-interval Subset of REAL
for b2 being Function of b1, REAL
for b3 being DivSequence of b1 st b2 is_bounded_on b1 & delta b3 is convergent_to_0 & vol b1 <> 0 holds
( upper_sum b2,b3 is convergent & lim (upper_sum b2,b3) = upper_integral b2 )
proof end;