Errata

Abstract Page 7/2, line 20, for parts, read part. Page 73, line 3, for between, read below. Page 98, line 4 from bottom, dele the comma after A. Page 101, line 6 from bottom, dele BH. Page 102, line 4, for axes, read axis. Page 164, line 11, dele the comma between m and n. Page 174, line 7, for consisted of read consisted in. Page 174, line last, for m, n, read m, m. Page 191, line 13, for ϕϕ-1x, read ϕ-1ϕx. Page 213, line 14, for ↓ϕ ↓ (x, y), read ϕϕ ↓ (x, y). Page 214, line 10, dele "in an infinite number of ways”. Page 224, line 22, for f (a), read f (x). Page 226, line 24, for = x, read = z. Page 232, line 16, in tbe denominator, for 1—, read 1+. Page 232, line 18, ditto, ditto, for 1—, read 1 ±. Page 251, line 9, for d↓ x, 1/y)/dx read d↓(x, 1/y)/dx Page 251, line 11, for din both numerator, read d2. Page 251, line 13, for (x/y) read x ϕ (x/y).