Package nltk_lite :: Package parse :: Module lambdacalculus :: Class Expression
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Class Expression

Known Subclasses:
ApplicationExpression, VariableBinderExpression, VariableExpression

The abstract class of a lambda calculus expression.
Method Summary
  __init__(self)
  __eq__(self, other)
  __hash__(self)
  __ne__(self, other)
  __repr__(self)
  __str__(self)
  equals(self, other)
Are the two expressions equal, modulo alpha conversion?
  free(self)
Set of free variables.
  replace(self, variable, expression)
Replace all instances of variable v with expression E in self, where v is free in self.
  simplify(self)
Evaluate the form by repeatedly applying applications.
  skolemise(self)
Perform a simple Skolemisation operation.
  subterms(self)
Set of all subterms (including self).
  variables(self)
Set of all variables.
  _skolemise(self, bound_vars, counter)

Method Details

equals(self, other)

Are the two expressions equal, modulo alpha conversion?

free(self)

Set of free variables.

replace(self, variable, expression)

Replace all instances of variable v with expression E in self, where v is free in self.

simplify(self)

Evaluate the form by repeatedly applying applications.

skolemise(self)

Perform a simple Skolemisation operation. Existential quantifiers are simply dropped and all variables they introduce are renamed so that they are unique.

subterms(self)

Set of all subterms (including self).

variables(self)

Set of all variables.

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