:: GOBOARD2  semantic presentation
defpred S1[  Nat] means for b1 being finite Subset of REAL   st b1 <>  {}  &  card b1 = a1 holds 
( b1 is bounded_above &  upper_bound b1 in b1 & b1 is bounded_below &  lower_bound b1 in b1 );
Lemma1: 
S1[0]
 
by CARD_2:59;
Lemma2: 
for b1 being  Nat  st S1[b1] holds 
S1[b1 + 1]
 
Lemma3: 
for b1 being  Nat holds  S1[b1]
 
from NAT_1:sch 1(Lemma1, Lemma2);
theorem Th1: :: GOBOARD2:1
theorem Th2: :: GOBOARD2:2
canceled; 
theorem Th3: :: GOBOARD2:3
theorem Th4: :: GOBOARD2:4
theorem Th5: :: GOBOARD2:5
theorem Th6: :: GOBOARD2:6
theorem Th7: :: GOBOARD2:7
theorem Th8: :: GOBOARD2:8
theorem Th9: :: GOBOARD2:9
theorem Th10: :: GOBOARD2:10
theorem Th11: :: GOBOARD2:11
theorem Th12: :: GOBOARD2:12
theorem Th13: :: GOBOARD2:13
theorem Th14: :: GOBOARD2:14
theorem Th15: :: GOBOARD2:15
theorem Th16: :: GOBOARD2:16
theorem Th17: :: GOBOARD2:17
theorem Th18: :: GOBOARD2:18
theorem Th19: :: GOBOARD2:19
theorem Th20: :: GOBOARD2:20
defpred S2[  Nat] means for b1 being   FinSequence of  REAL   st  card (rng b1) = a1 holds 
ex b2 being   FinSequence of  REAL  st 
(  rng b2 =  rng b1 &  len b2 =  card (rng b1) & b2 is increasing );
Lemma15: 
S2[0]
 
Lemma16: 
for b1 being  Nat  st S2[b1] holds 
S2[b1 + 1]
 
Lemma17: 
for b1 being  Nat holds  S2[b1]
 
from NAT_1:sch 1(Lemma15, Lemma16);
theorem Th21: :: GOBOARD2:21
defpred S3[  Nat] means for b1, b2 being   FinSequence of  REAL   st  len b1 = a1 &  len b2 = a1 &  rng b1 =  rng b2 & b1 is increasing & b2 is increasing holds 
b1 = b2;
Lemma18: 
S3[0]
 
Lemma19: 
for b1 being  Nat  st S3[b1] holds 
S3[b1 + 1]
 
Lemma20: 
for b1 being  Nat holds  S3[b1]
 
from NAT_1:sch 1(Lemma18, Lemma19);
theorem Th22: :: GOBOARD2:22
definition
let c1, 
c2 be  
increasing  FinSequence of  
REAL ;
assume E21: 
( 
c1 <>  {}  & 
c2 <>  {}  )
 ;
func  GoB c1,
c2 ->   Matrix of 
(TOP-REAL 2) means :
Def1: 
:: GOBOARD2:def 1
(  
len a3 =  len a1 &  
width a3 =  len a2 & ( for 
b1, 
b2 being  
Nat  st 
[b1,b2] in  Indices a3 holds 
a3 * b1,
b2 = |[(a1 . b1),(a2 . b2)]| ) );
existence 
ex b1 being  Matrix of (TOP-REAL 2) st 
(  len b1 =  len c1 &  width b1 =  len c2 & ( for b2, b3 being  Nat  st [b2,b3] in  Indices b1 holds 
b1 * b2,b3 = |[(c1 . b2),(c2 . b3)]| ) )
 
uniqueness 
for b1, b2 being  Matrix of (TOP-REAL 2)  st  len b1 =  len c1 &  width b1 =  len c2 & ( for b3, b4 being  Nat  st [b3,b4] in  Indices b1 holds 
b1 * b3,b4 = |[(c1 . b3),(c2 . b4)]| ) &  len b2 =  len c1 &  width b2 =  len c2 & ( for b3, b4 being  Nat  st [b3,b4] in  Indices b2 holds 
b2 * b3,b4 = |[(c1 . b3),(c2 . b4)]| ) holds 
b1 = b2
 
 
end;
 
:: deftheorem Def1   defines GoB GOBOARD2:def 1 : 
:: deftheorem Def2   defines Incr GOBOARD2:def 2 : 
:: deftheorem Def3   defines GoB GOBOARD2:def 3 : 
theorem Th23: :: GOBOARD2:23
theorem Th24: :: GOBOARD2:24
theorem Th25: :: GOBOARD2:25
theorem Th26: :: GOBOARD2:26
theorem Th27: :: GOBOARD2:27
theorem Th28: :: GOBOARD2:28
theorem Th29: :: GOBOARD2:29