Glossary

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accessible (or reachable, or initially connected)

A state $s$ is accessible if there is a path from an initial state to $s$.

An automaton is /accessible/ if all its states are.

See:

• automaton.accessible.
• automaton.is_accessible.

Antimirov automaton

See derived-term automaton.

derived-term automaton

See expression.derived_term.

equation automaton

See derived-term automaton.

has_lightening_cycle

A lightening cycle is a path from a state to itself that is either negative (for $\mathbb{Q}$, $\mathbb{R}$ and $\mathbb{Z}$), or between 0 and 1 (for $\mathbb{Q}$, $\mathbb{R}$ and $\mathbb{R}_\text{min}$).

is_commutative

A valueset is commutative if mul(u, v) == mul(v, u).

is_free

A labelset is free if the labels are only "letters". This is a requirement for algorithms such as determinize, evaluate.

• letterset is free.
• nullableset is not free.
• oneset is not free.
• wordset is not free.
• tupleset is free if its components are free.

If the labelset is free, then label_t is letter_t.

is_idempotent

A valueset is idempotent if add(v, v) == v.

is_letterized

A labelset is letterized if it free, or nullable of free. In other words, its labels are either letters, or the empty word. Maybe surprisingly, oneset ($\{1\}$) is letterized.

partial-derivative automaton

See derived-term automaton.

position automaton

See standard automaton.