diff options
Diffstat (limited to 'src/algebra/perman.spad.pamphlet')
| -rw-r--r-- | src/algebra/perman.spad.pamphlet | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/algebra/perman.spad.pamphlet b/src/algebra/perman.spad.pamphlet index bc2f63f1..2fa6e43d 100644 --- a/src/algebra/perman.spad.pamphlet +++ b/src/algebra/perman.spad.pamphlet @@ -135,7 +135,7 @@ Permanent(n : PositiveInteger, R : Ring with commutative("*")): ++ some modifications are necessary: ++ \item 2. if {\em n > 6} and R is an integral domain with characteristic ++ different from 2 (the algorithm works if and only 2 is not a - ++ zero-divisor of R and {\em characteristic()$R ^= 2}, + ++ zero-divisor of R and {\em characteristic()$R ~= 2}, ++ but how to check that for any given R ?), ++ the local function {\em permanent2} is called; ++ \item 3. else, the local function {\em permanent3} is called @@ -166,7 +166,7 @@ Permanent(n : PositiveInteger, R : Ring with commutative("*")): -- For the meaning of the elements of vv, see GRAY. w : V R := new(n,0$R) j := 1 -- Will be the number of the element changed in subset - while j ^= (n+1) repeat -- we sum over all subsets of (1,...,n) + while j ~= (n+1) repeat -- we sum over all subsets of (1,...,n) sgn := -sgn b := sgn if vv.1.j = 1 then k := -1 @@ -211,7 +211,7 @@ Permanent(n : PositiveInteger, R : Ring with commutative("*")): b := b * w.i a := a+b j := 1 -- Will be the number of the element changed in subset - while j ^= n repeat -- we sum over all subsets of (1,...,n-1) + while j ~= n repeat -- we sum over all subsets of (1,...,n-1) sgn := -sgn b := sgn if vv.1.j = 1 then k := -1 @@ -256,7 +256,7 @@ Permanent(n : PositiveInteger, R : Ring with commutative("*")): b := b *$R w.i a := a +$R b j := 1 -- Will be the number of the element changed in subset - while j ^= n repeat -- we sum over all subsets of (1,...,n-1) + while j ~= n repeat -- we sum over all subsets of (1,...,n-1) sgn := -sgn b := sgn if vv.1.j = 1 then k := -1 |