biginteger and bigfloat vectors support the standard comparison operations. The base R documentation can be found at Comparison.
A logical vector.
Other bignum operations: 
bignum-arith,
bignum-math,
bignum-special
x <- biginteger(5)
y <- bigfloat(2)
x < y
#> [1] FALSE
x > y
#> [1] TRUE
x <= y
#> [1] FALSE
x >= y
#> [1] TRUE
x == y
#> [1] FALSE
x != y
#> [1] TRUE