Equalizer of two parallel ACSet transformations

Given f, g: A → B, compute the subobject of A where f and g agree.

Usage

equalizer(f, g)

Arguments

f

ACSetTransformation A → B

g

ACSetTransformation A → B

Value

List with equalizer (ACSet) and incl (inclusion morphism)

Examples

A <- Graph(V = 2)
B <- Graph(V = 2)
f <- ACSetTransformation(list(V = c(1L, 2L), E = integer(0)), A, B)
g <- ACSetTransformation(list(V = c(1L, 1L), E = integer(0)), A, B)
eq <- equalizer(f, g)
nv(eq$equalizer) # 1 (only vertex 1 agrees)
#> [1] 1