removeContradictions

removeContradictions

removeContradictions Remove contradicting terms from a transmission condition.

q = removeContradictions(q) removes terms that contain contradictions of the form x_i & !x_i, which always evaluate to false and contribute zero to the transmission effect. Behaviour of the function can be changed by setting REMOVECONTRADICTIONS=false locally.

Arguments: - q (Q): A transmission condition. See also Q and makeCondition.

Returns: - If REMOVECONTRADICTIONS is set to false, the input q is returned unchanged. - If REMOVECONTRADICTIONS is true or not set: 1. If all terms are contradicting, Q("T", 0) is returned, which represents a transmission effect of zero. 2. If some terms are non-contradicting, only the non-contradicting terms are retained in the output.

Example

setRemoveContradictions(true); % on by default

q = Q('x1', 1);
q = removeContradictions(q); % Returns q unchanged (no contradictions).

q = Q('x1 & !x1', 1);
q = removeContradictions(q); % Returns Q('T', 0).

q = Q({'x1 & !x1', 'x1 & x2'}, [1, 1]);
q = removeContradictions(q); % Returns Q('x2 & x1', 1).

setRemoveContradictions(false);

q = Q('x1 & !x1', 1);
q = removeContradictions(q); % Returns the original q.

Notes

• If REMOVECONTRADICTIONS is not explicitly set, contradictions are removed by default.