Lapping — where it appears
Named by 2 essays across one field — each of them below, with the objects they name alongside it.
Also named here as tricot, warp knitting — the same set of essays touches all of them, so they are one junction rather than several.
Warp knitting, which is a different thing entirely
Every wale has its own thread, and if the thread never leaves its wale the fabric is a set of independent cords. Whether a lapping makes cloth is decided by a coprimality condition — the satin theorem, in a knit.
What a second guide bar is for
One warp-knit bar leaves the wales in as many independent fabrics as its shog shares factors with the width. Two bars leave the greatest common divisor of both — so a pair of shogs that each fail alone can succeed together, and a pair that share a factor cannot.
Named alongside it
The objects these essays reach for when they reach for this one.
TricotWaleWarp knittingCloth integrityConnectivityGreatest common divisor