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These functions test for the logical relation between two periods according to Levy's typology (Levy et al. 2021; Levy 2025) .

Usage

starts_before_end_of(x, y, strict = FALSE)

ends_after_start_of(x, y, strict = FALSE)

starts_before_start_of(x, y, strict = FALSE)

starts_after_start_of(x, y, strict = FALSE)

ends_before_end_of(x, y, strict = FALSE)

ends_after_end_of(x, y, strict = FALSE)

ends_before_start_of(x, y, strict = FALSE)

starts_after_end_of(x, y, strict = FALSE)

meets(x, y, strict = FALSE)

met_by(x, y, strict = FALSE)

contemporary_with(x, y, strict = FALSE)

starts_during(x, y, strict = FALSE)

includes_start_of(x, y, strict = FALSE)

ends_during(x, y, strict = FALSE)

includes_end_of(x, y, strict = FALSE)

starts_with(x, y, strict = FALSE)

ends_with(x, y, strict = FALSE)

overlaps_before(x, y, strict = FALSE)

overlaps_after(x, y, strict = FALSE)

includes(x, y, strict = FALSE)

included_in(x, y, strict = FALSE)

begins(x, y, strict = FALSE)

begun_by(x, y, strict = FALSE)

ends(x, y, strict = FALSE)

ended_by(x, y, strict = FALSE)

equal_to(x, y, strict = FALSE)

Arguments

x, y

Pair(s) of periods to test the relation between. Can be interval() objects, two-element numeric vectors, or lists of two-element numeric vectors.

strict

By default, comparison is inclusive (i.e. using <= and >=). Use strict = FALSE for strict comparison (i.e. using < and >).

Value

Logical vector the same length as x and y.

References

Levy E (2025). “Temporal relations in archaeology: a survey and a new typology.” Archaeometry, 67(S1), 178–199. doi:10.1111/arcm.13080 .

Levy E, Geeraerts G, Pluquet F, Piasetzky E, Fantalkin A (2021). “Chronological networks in archaeology: A formalised scheme.” Journal of Archaeological Science, 127, 105225. doi:10.1016/j.jas.2020.105225 .

Examples

period1 <- c(1500, 1900)
period2 <- c(1800, 1950)
period3 <- c(1900, 1950)

contemporary_with(period1, period2)
#> [1] TRUE

# Inclusive relations (the default)
contemporary_with(period1, period3)
#> [1] TRUE

# Strict relations
contemporary_with(period1, period3, strict = TRUE)
#> [1] FALSE