Victor Porton's Math Weblog

Significantly updated theory of dependencies (algebraic theory of formulas).

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Additions to the online article:

• Concept of disjunctive pseudomorphism, which is an important special case of pseudomorphism, plus several related theorems.
• Detailed analysis of factor of two constructs (the function which transforms one expression to an other expression, used e.g. in pattern matching).
• Stated and proved the theorem about criterion of pseudomorphic image (when B is strict ancestry pseudomorphic image of A), generalizing the analogous criterion in old theory of formulas.
• Criterion of a function to be a factor of two constructs.

Some theorems (e.g. about existence of no more than one strict ancestry pseudomorphism) are generalized for the case of disjunctive pseudomorphism.