Virtual knots whose Delta unknotting numbers equal one

Satoh and Taniguchi defined a virtual knot invariant [Formula: see text] called the [Formula: see text]-writhe for each non-zero integer [Formula: see text]. The [Formula: see text]-writhes give the coefficients of some polynomial invariants for virtual knots including the index polynomial, the odd writhe polynomial and the affine index polynomial. Higa, Nakamura, Nakanishi and Satoh introduce the polynomial invariant called the intersection polynomial. In this paper, we construct infinitely many virtual knots [Formula: see text] ([Formula: see text]) whose Delta unknotting numbers equal one. Delta unknotting number one knots have the same [Formula: see text]-writhes and the same intersection polynomials as the trivial knot.