Thm* n: , f:( n  ), i: (n-1). sum(f((i, i+1)(x)) | x < n) = sum(f(x) | x < n) | [sum_switch] |
Thm* n: , f:( n  ), m: (n+1).
Thm* sum(f(x) | x < n) = sum(f(x) | x < m)+sum(f(x+m) | x < n-m) | [sum_split] |
Thm* n: , f:( n  ), m,k: n.
Thm* m = k
Thm* 
Thm* ( x: n. x = m  x = k  f(x) = 0)  sum(f(x) | x < n) = f(m)+f(k) | [pair_support] |
Thm* n,k: , c:( n  k).
Thm* p:( k ( List)).
Thm* sum(||p(j)|| | j < k) = n
Thm* & ( j: k, x,y: ||p(j)||. x<y  (p(j))[x]>(p(j))[y])
Thm* & ( j: k, x: ||p(j)||. (p(j))[x]<n & c((p(j))[x]) = j) | [finite-partition] |
Thm* n: , f:( n  ), m: n.
Thm* ( x: n. x = m  f(x) = 0)  sum(f(x) | x < n) = f(m) | [singleton_support_sum] |
Thm* n: , f:( n  ). ( x: n. f(x) = 0)  sum(f(x) | x < n) = 0 | [empty_support] |
Thm* n: , f:( n  ), m: n.
Thm* sum(f(x) | x < n) = f(m)+sum(if x= m 0 else f(x) fi | x < n) | [isolate_summand] |
Thm* k: , f,g:( k  ), p:( k  ).
Thm* sum(if p(i) f(i)+g(i) else f(i) fi | i < k)
Thm* =
Thm* sum(f(i) | i < k)+sum(if p(i) g(i) else 0 fi | i < k) | [sum-ite] |
Thm* k,b: , f:( k  ). ( x: k. b f(x))  b k sum(f(x) | x < k) | [sum_lower_bound] |
Thm* k,b: , f:( k  ). ( x: k. f(x) b)  sum(f(x) | x < k) b k | [sum_bound] |
Thm* k: , f,g:( k  ).
Thm* ( x: k. f(x) g(x))  sum(f(x) | x < k) sum(g(x) | x < k) | [sum_le] |
Thm* n: , f,g:( n  ), d: .
Thm* sum(f(x)-g(x) | x < n) = d  sum(f(x) | x < n) = sum(g(x) | x < n)+d | [sum_difference] |
Thm* n: , f,g:( n  ).
Thm* ( i: n. f(i) = g(i))  sum(f(x) | x < n) = sum(g(x) | x < n) | [sum_functionality] |
Thm* n: , a: . sum(a | x < n) = a n | [sum_constant] |
Thm* n: , f,g:( n  ).
Thm* sum(f(x) | x < n)+sum(g(x) | x < n) = sum(f(x)+g(x) | x < n) | [sum_linear] |
Thm* n: , f:( n  ). ( x: n. 0 f(x))  0 sum(f(x) | x < n) | [non_neg_sum] |
Def sum(f(x;y) | x < n; y < m) == sum(sum(f(x;y) | y < m) | x < n) | [double_sum] |