author  paulson 
Tue, 12 Dec 2000 12:01:19 +0100  
changeset 10648  a8c647cfa31f 
parent 10606  e3229a37d53f 
child 10752  c4f1bf2acf4c 
permissions  rwrr 
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(* Title : Real/RealDef.thy 
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ID : $Id$ 
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Author : Jacques D. Fleuriot 
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Copyright : 1998 University of Cambridge 

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Description : The reals 

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*) 

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RealDef = PReal + 

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constdefs 

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realrel :: "((preal * preal) * (preal * preal)) set" 

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"realrel == {p. ? x1 y1 x2 y2. p = ((x1,y1),(x2,y2)) & x1+y2 = x2+y1}" 

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typedef real = "UNIV//realrel" (Equiv.quotient_def) 
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instance 

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real :: {ord, zero, plus, times, minus, inverse} 
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consts 

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"1r" :: real ("1r") 

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defs 

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real_zero_def 
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"0 == Abs_real(realrel^^{(preal_of_prat(prat_of_pnat 1p), 
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preal_of_prat(prat_of_pnat 1p))})" 
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real_one_def 
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"1r == Abs_real(realrel^^{(preal_of_prat(prat_of_pnat 1p) + 
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preal_of_prat(prat_of_pnat 1p),preal_of_prat(prat_of_pnat 1p))})" 
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real_minus_def 

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" R == Abs_real(UN (x,y):Rep_real(R). realrel^^{(y,x)})" 
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real_diff_def 

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"R  (S::real) == R +  S" 

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real_inverse_def 
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"inverse (R::real) == (SOME S. (R = 0 & S = 0)  S * R = 1r)" 
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real_divide_def 
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"R / (S::real) == R * inverse S" 

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constdefs 
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real_of_preal :: preal => real 
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"real_of_preal m == 
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Abs_real(realrel^^{(m+preal_of_prat(prat_of_pnat 1p), 
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preal_of_prat(prat_of_pnat 1p))})" 
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real_of_posnat :: nat => real 
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"real_of_posnat n == real_of_preal(preal_of_prat(prat_of_pnat(pnat_of_nat n)))" 
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parents:
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real_of_nat :: nat => real 
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"real_of_nat n == real_of_posnat n + (1r)" 
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defs 

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real_add_def 

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"P + Q == Abs_real(UN p1:Rep_real(P). UN p2:Rep_real(Q). 

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(%(x1,y1). (%(x2,y2). realrel^^{(x1+x2, y1+y2)}) p2) p1)" 
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real_mult_def 

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"P * Q == Abs_real(UN p1:Rep_real(P). UN p2:Rep_real(Q). 

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(%(x1,y1). (%(x2,y2). realrel^^{(x1*x2+y1*y2,x1*y2+x2*y1)}) p2) p1)" 
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real_less_def 

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"P < Q == EX x1 y1 x2 y2. x1 + y2 < x2 + y1 & 

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(x1,y1):Rep_real(P) & 

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(x2,y2):Rep_real(Q)" 

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real_le_def 

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"P <= (Q::real) == ~(Q < P)" 

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end 