English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

There is an elegant relation found by Fabricius-Bjerre [Math. Scand 40 (1977)20--24] among the double tangent lines, crossings, inflections points, andcusps of a singular curve in the plane. We give a new generalization tosingular curves in RP^2. We note that the quantities in the formula arenaturally dual to each other in RP^2, and we give a new dual formula.Comment: This is the version published by Algebraic & Geometric Topology on 19  November 200

Invariants of curves inRP2andR2

Invariants of curves inRP²andR²